Based on my experiences, referrals are a negative factor in both approvals and SUB availability. Several times after a popup or rejection I repeated an app (after some waiting period), and it sailed through. So I strongly suspect that this bank is quite thrifty in paying out referrals.
Of course closing accounts is known negative factor as well.

Thanks for posting this.... if Im reading correctly, one may first try to use a referral link to apply and get the pop-up, and then try using a standard AmEx link without a specific referral and get approved.... am I reading this correctly...? Furthermore, would it be smart(er) to perhaps try the non referral application from a different computer/browser etc. so as to additionally increase approval chances...?

Thank you !!
Gaucho100K

If you're interested in a new account, run a comparison shortly before the app. Referred links can be either higher or lower than non-referred links, and they can change unpredictably. Once you decided which is the most attractive option, it does makes sense to try it first.

Run a comparison...? Sorry, could you elaborate...? Im not sure Im following...

Thanks !

CC application links can potentially from these sources: referred links originating from different cards belonging to friends or family, anonymous links from the bank's website, targeted links specifically for you (available when you're signed in). All of them may have different offers.

I applied for a few Amex a few days ago, each got PUJ so I tried and withdrew each, figuring it wouldn't do any damage since withdrawn apps don't hit the CB. Today I applied for a NLL and got the message "we have received multiple applications from you recently and you have reached the maximum number of applications we will accept." Whoa, did not know withdrawn applications count towards an application limit. I was only aware of the 1/5 and 2/90 rule for new approvals.

Wow, they're getting strict :(.