Is it a disciplinary violation for department leaders to ask their subordinates to hand over part of their year-end bonuses as activity funds?

There is no clear provision in any corporate rules and regulations that the part of the year-end bonus should be turned over as activity funds. This move must be just the intention of the department leaders. If there is a clear management mechanism for the fees submitted, and the future expenses are indeed used for the department's public expenses, and there are rules and regulations, this is not a disciplinary violation. But this move is definitely unreasonable and you can give feedback to the company leaders.