Hi Yan,
So the difference between the ‘Force generate’ in BP vs. the ‘Force generate (& implicit flush cache)’ is really a question of the cache being flushed.
What happens in this case is that your ‘Get Actor Property’ node result is cached, and the process you’ve used to add the tags hasn’t trigger a change that we’re tracking, hence not only is the graph not regenerating by itself, it will also not do anything different.
In your case, there might be something you can do to force a notification (not quite sure what exactly unfortunately), but otherwise you could try to flush the cache as well - it’s on the PCG subsystem, called ‘Flush Cache’. This is the nuclear option, but it might not be a problem in your case.
I’ll ask a second opinion in the team for the notification thing, but otherwise the flush solution might work for you.
Cheers,
Julien