Update:
I had to wait 18 days for the withdrawals, then after a month, i gave another shot. it was working fine for 2 transactions than again bhoom
experienced same (validating) issue 3 more times. After the 2nd experience, the 3rd and 4th withdrawal delays were back to back. 2nd took 3 days, and then 3rd and the 4th delay was 2 days. there is no use of selecting high fee for fast withdrawal.
(Note: this delay was not from blockchain confirmations. Xapo team were not releasing the withdrawal by their side) once Xapo accepts/validates withdrawal, then the additional standard blockchain confirmation time is 30 to 60 minutes that too because of the high withdrawal fee. (when Xapo takes days to release the withdrawals then paying high withdrawal fee is a joke) (The weird part is this experience repeats during the bitcoin price drops (It's not a scam (yet), but definitely BTC kidnapping)
I will be avoiding them until they fix this issue.
(but as per their chat support' this is not an error/issue, it happens auto by their security software, so they can't promise instant withdrawals for future transactions).