It’s Santander. Be alert yes, but let us be cautious about where we lay any blame until we have sufficient or specific facts. I have had several years of using them+Bisq for my transactions without any problem, it may continue that way when this current problem is resolved or the automated fraud detection threshold may need tuning and be too sensitive and make it practical to use them with online banking for now?
The difficulty appears to be with their security team, or whoever, not being sufficiently quick, responsive, informative or respectful to resolve this issue. I am compiling a list of complaints to submit through the bank’s complaints procedure.