The Club Intercontinental Lounge does not serve breakfast currently.
Instead breakfast is available as buffet served at the Brasserie.
The hotel could go by the letter of IHG T&C,
https://www.ihg.com/content/us/en/customer-care/member-tc/2nd-page
Lounge Membership provides access to the hotel’s Club Lounge and offered amenities within the physical space (e.g., library, meeting room, and business station) for the registered Member plus one additional guest for the duration of their stay or until time of Check-Out. (Note: At Iberostar Beachfront Resorts the one additional guest must be a guest at the hotel.)
- Annual Lounge Membership is available at IHG properties with a Club Lounge unless restricted due to renovations, closures, or other facility limitations
- Annual Lounge Membership does not include Club REGENT or Club InterContinental amenities or services beyond the physical lounge, e.g., free pressing, farewell amenity, airport transportation, etc
Royal Ambassador Complimentary Club InterContinental lounge access.- Applicable only where the hotel has a dedicated Club InterContinental lounge.
- Valid for two people including the member, staying in the member's room only.
- Where the hotel does not operate a dedicated Club InterContinental lounge, Royal Ambassador members will be given two complimentary full breakfasts for each night of the stay in the main restaurant for the member and one registered guest staying in the member’s room.
Note: if the Royal Ambassador member chooses the Welcome Amenity Free breakfast for two, they will only receive up to two breakfasts, which will be for the member plus one additional guest staying in the member’s room.
Meaning.....
Annual lounge pass holders can only enjoy the physical Club Intercontinental Lounge space and F&B therein.
Anything outside that realm is excluded.
Thus according to t&c annual lounge pass holders cannot enjoy complimentary breakfast at the Brasserie.
For that opportunity one must be diamond and select as welcome amenity: breakfast.
Also RA enjoys club lounge access but only enjoys complimentary breakfast in the restaurant if a hotel has no lounge.
Yet,
fortunately
Because the Club Intercontinental Lounge currently does not serve breakfast,
this hotel still allows annual lounge pass holders also breakfast at the Brasserie,
And fortunately RA can also enjoy breakfast at the Brasserie.
So what's
always available at the Club Intercontinental lounge and self service?

That was the nibbles . Stays the same every day.
Now the drinks that are self service

À volonté :
- cold tea
- infused water
- mineral water
- sparkling water
Hot beverages and other soft drinks are not selfservice and can only be acquired by approaching the servers.
Afternoon tea
15 - 17 H
A snack plate is picked up from the kitchen and brought to you by a server.
There is no choice or buffet.

Afternoon tea is described by staff as just a snack platter.
Evening presentation
From
17 - 19 H evening
Buffet is available.
Cold choices are:

More a light nibble but will not substitute a meal
Hot choices are:

Covers a light feeling of peckishness
And the complimentary alcohol available at the Club Intercontinental lounge selfservice :

There was no other drinks menu on display or to be found.
Mineral water, sparkling water, infused water and cold tea are selfservice as shown above in the post.
If you desire any other softdrinks or hot beverages, you must ask the servers and be served.
Royal Ambassadors have long been leeching the same cost from lounge operations as do pass holders.
IHG can strictly control yearly the amount of Royal Ambassadors.
Culling RA and weeding out RA is easy for IHG due to the "undisclosed" criteria.
IHG decides how many RA in the ecosystem. It is per invitation only.
IHG can reduce the amount of RA lounge leeches at own whim yearly at 31 DEC/1JAN.
Royal Ambassadors cannot enjoy complimentary access at Regent, Crown Plaza, Voco, Holiday Inn's lounges
Those with annual lounge pass can enjoy complimentary lounge access at Regent, Intercontinental, Crown Plaza, Voco, Holiday Inn's lounges.
IHG cannot control how many people actually earn the annual lounge pass.
Yes IHG set the treshold at 40/70N to be acquired. They can make the annual lounge pass easier or harder to acquire for everyone. If reaching thr criteria thresholds, the annual lounge pass is granted.
So everyone can attempt 40/70N and be granted the annual lounge pass if succesful at 40/70 N.
But there is no control/prediction of the total amount of persons reaching 40/70N.
The sheer volume of people acquiring the annual lounge pass holders can fluctuate in random.
(comparison: anyone US-based can get the US Hilton Aspire creditcard, thus unpredictable amount of influx of auto-granted Hilton Honnnors Diamonds)
Your statement of
Royal Ambassadors have long been leeching the same cost from lounge operations as do pass holders.
needs thus a different perception.
With IC Istanbul, i see its owner providing a very calculating limiting offering in Club F&B.
As you can see above in my photos.
- during the day other than water, all other nonalcoholic/hot beverages are not self service
- afternoon tea is a snack plate
- evening service : 1 soup, 2 hot snacks, basic cold buffet
- evening service : although selfservice alcohol andcold tea and waters, still other softdrinks / hot beverages are served upon request by waiters
- the evening service alcohol / cocktail menu as posted upthread by
f0zzyNUE is gone,
https://www.flyertalk.com/forum/37025323-post218.html
what you see on the buffet only, is only what you can get.
Other requests are now extra. Staff are warning about it.
Thus currently a rather very toned down offering implying that management has viewed IC Istanbul's Club Intercontinental Lounge as shifted from being a profit center to a cost center and beancounters are implementing measures to curb excesses and control volumes in food & drink consumption, quantities and quality.
That's my honest opnion, experience and insitu observation.