Cyprus isn’t in schengen but is in the EU. you can stay up to 90 days in any 180 day period.

Doesn’t the Schengen 90 day limit stand separate to the individual country limits for any non-schengen eu country?

I suspect it's more a case of blasč, much like the Spanish attempt at checking passports, rather than an official rule.

As Karfa mentioned above, Cyprus isn't part of Schengen area.

https://www.gov.uk/foreign-travel-ad...y-requirements

​​​​​​As Cyprus is not in the Schengen area, any time you spend in the Schengen area does not affect the number of days you can spend in Cyprus, but, officially, Cyprus still has a 90 days in 180 days rule.

Cyprus has also indicated that it would like to become part of the Schengen area.

Yes, for Cyprus it’s 90 days in any 180 day period in Cyprus. Visits to other EU/Schengen countries do not count.

I visit the nordics regularly and have noticed the number of question I’m asked at the immigration desk has gone up from a maximum of one to half a dozen or so recently.

I did an ex-EU from ARN (SAS Gold trip!) in February and don’t recall the specific questions I was asked, but also don’t recall being worried about not getting into the country! Perhaps the way a question was answered, or the way the answer was perceived, triggered the immigration officer. I tend to just say I’m there as a tourist rather than saying I’m there for a tier point run or just for the sake of flying.

In my experience entering the Nordic countries with a UK passport does attract greater entry scrutiny than other Schengen area borders in terms of both the 90 day rule and purpose of visit with Sweden being the most inquisitorial and pedantic. Helsinki can also ask a lot a questions but they seem more geared to transit entry due to the connecting flight model Finnair use.

Extra questions crossing the border in Sweden, Norway or Finland with an overnight connections or when I've entered Schengen through a different country border so they can't easily reconcile the length of time spent in the Schengen area is typical. I also notice the Nordic border officers take a lot more care ensuring entry and exit stamps are inserted neatly and adjacent to one another whereas Mediterranean country officials seem to place stamps randomly.

Refusal of entry sounds like this particular immigration office was taking it to a higher level. Did the Op's husband have a confirmed hotel reservation for the night in addition to evidence of the departing flight the next morning?

Now that you mention it, I did get a few more questions when entering at OSL. I had arrived on BA and was departing the next day on QR. Said it was my overnight connection and that I was planning on going shopping while I'm there, specifically Lakrids by Bulow (no joke!). The agent found this hilarious and let me pass.

Gothenburg last year was the only time in 40 years of flying that I was ever made to actually produce my hotel reservation confirmation. Sometimes when entering the USA they ask where I am staying – but when I reply with an establishment name that’s all I ever need to do.

I can confirm I've had a grilling at CPH from Immigration Officials when passing through to the Schengen area. Also recently when travelling to OTP (asking for when I was returning, how many days I was staying, etc).

I must say I find this hard to believe. I am sure this happened of course, but is there any more context to this?
UK passport is one of the most valuable in the world, with UK being the 6th largest economy developed nation. I can't see anyone being turned away in EU/Schengen if all valid documents under visa waiver agreements. Staying overnight for a flight is not typically an issue. In some EU/Schengen airports there are even automated kiosks and no need to see immigration (CDG for instance).
To say this is highly unusual, is an understatement. Perhaps there is more context to this, not that I blame the poor guy but we don't know how frequently he travels to EU, duration etc There is not enough info in the OP's post to really dig into any depth with this.

EDIT: USA is an exception but I have long stopped considering that place a proper developed country lol

lack of reciprocity annoys me, EU travelers can breeze through automated gates at LHR, whereas us Brits have to typically use manual desks. Heathrow should disable automated gates for EU passports until reciprocity is established. I don't have skin in the game , as I also have EU citizenship though need to renew my second passport and am EU born, so can criticise from certain degree of objectivity here

The UK does this for financial reasons. Automate everything possible to save on the cost of a border officer.

I have often wondered about the EU automated gates. For instance from LHR if I take BA into Munich T1 I still have to get the physical stamp in my Canadian passport but if I then leave from MUC T2 I can use the automated gates to exit. I've never done this because I don't like the idea there is a stamp in my passport for entering but none leaving. Just think it would cause an unnecessary hassle. Hopefully if ETIAS ever gets up and running this stamping will be a thing of the past

You'll get stamped on exit immediately after passing the gate by an officer