I mean yeah I guess a bug is clearly mildly infuriating. But it's also a bug. And the way your title is phrased, it's like PayPal is intentionally preventing you from removing your card. Which it doesn't seem to be pointing to here. Like I could imagine if they don't want to let you have no cards on your account without completely closing the account. But the message would say something like that. Like "you're required to have at least one valid card on your account. " The message isn't just going to say something like "please try again later" unless its a bug. That's just telling you that a bug happened and you may need to contact customer support to resolve it.
In my country insurances won't let you buy one that is necessary-to-drive by adding such "bugs" and impossible captchas for newbie drivers and motorcyclists. Works like a charm in a court - they just say it was a bug
PayPal is notorious for displaying meaningless errors for just about everything, even when it is intentional. Might not be the case here, but they definitely do things like this.
Though if I had to put my money on it, if it isn’t a bug it’s an anti fraud measure of some sort.
I worked for them. I've seen their list of error code reasons. Literally one of the error codes you could get was labelled as 'WTF happened?' on the list.
'Too many buckets' was another one, that one made me laugh tbh.
But they literally have like a 12+ page document of error codes and what they mean. The system is pretty buggy.
But generally our solution was, clear cache and cookies or try a different browser. It 75% of the time worked. If that didn't work, customer service could remove cards for you.
For me, PayPal said nothing until I called them. I made an expensive purchase via PayPal, they bounced it back with no notification that it was bounced back whatsoever, making it a headache for me and the seller. I had to make sure that it wasn't going out twice, which thankfully it didn't but the lack of an error message or anything was so unhelpful.
I just used my card straight-up after that. The card was under Visa, so it was subject to Visa's checks as well as the bank's own (where you can use SMS or app-based verification).