My old chimes dinged during video doorbell install

I have a front and back doorbell that share a chime. Per instructions, i connected the fuse wire to the post marked “front” after disconnecting the wire from the post marked “front”. I then connected the other end of the fuse wire to the post marked “trans,”

Doorbell running really hot at night, ambient temp is 75F. I disconnected the doorbell and measured voltage from the doorbell wires, 22.5 volts. Within spec. I then measured amperage which of course lets current pass. With no load, not great for my transformer but it was a very brief measurement. When i touched the doorbell wires with multimeter leads, my old doorbell chimes… chimed.

Since i had disconnected the wire from the post marked “front” in the chime box, shouldn’t it have not chimed?

I’m exploring the overheating issue separately but curious about my doorbell engaging Old chimes when i thought it couldn’t.

Thanks!

Is the fuse still connected to the "front "post? From the install instructions the fuse should be connected to the wire that was disconnected from the “front” post. The fuse itself should not be connected to the front post, only the wire that was there.

Does your wiring look like the visual aid install instructions above?

I misspoke. I connected the front wire with the fuse wire, other end of fuse wire to trans post

Yes my install matches the depiction above