Seth Thomas strike problem

by Kim
(Lawrenceville, GA, US)

I have a Seth Thomas mantel clock (89 AL made in the USA) that runs beautifully and keeps wonderful time. The only problem is that every time I wind it, the strike number gets messed up. Sometimes it will even strike for maybe 20 times. I can adjust the hands and "fix" the immediate problem, but the next time I wind it the same thing will happen again.

This just started. Before, it was working just fine.
Any thoughts would be greatly appreciated!

Thank you!