Please change your password, your team may be hacked and someone might be pulling a prank on you. Also, make sure to logout once done playing.
This is the only logical explanation along with one specific problem that is occurring on rare cases when an economy update fails, so some changes made to related things during can be inadvertently reverted. I don't think this is what happened since it's specifically happening on Sundays and normally doesn't affect training.
Also, changing the training type once training has already started will, of course, not take effect.
Hope this helps.