It's not possible to identity a reason via the public forum. All that can be said is that any transaction can be a candidate for a review - can be a random security review, can be the number of transactions done within a certain time frame, amount of transaction, user account history of refunds, claims and/or disputes, etc.
I have made several transfers to the same bank for the last 6 months in the last 2 weeks I have had this happen. It's frustrating to say the least, I have found there is no real answer because it is the computer security program that does it. I have no limits no holds no nothing on my account than this. It is awful especially if you need that money right then. The customer service cannot do a thing about it even though it's easy to get angry with them and I have it's not their fault. I think PayPal needs to re-assess their security software. Hope this helped@
