Battery Running Out ?

I've had a Ladies Vintage F1 watch in my drawer for some time. I got it this morning and something rather odd is happening - something I've never seen before. The second had stays still for a few seconds and will then jump forward three, four or even five seconds; the movement is not continuous. Does this mean the battery is running out or something else ? The watch itself is 25 years old and - even allowing for this bizarre occurrence - still keeps remarkably good time. Any advice would be gratefully received. Many thanks

Yep, that is an indication that the battery is getting low and needs replaced soon.

EOL indicator (battery "End Of Life"). It's a "feature" that warns you that the battery is getting low. Get the battery changed as it's not a good idea to leave a dead battery in a watch due to risk of acid leakage.