Transformer keep some energy while powering machines

While providing power to the batteries or machines, transformers sometimes charge a little and keep that charge. This behavior is not deterministic because sometimes in exactly the same setup it don't hold any charge while powering. I think that it have something with build order because when I destroy setup and rebuild it I get different results. Sometimes only one transformed keep charge and other don't do that, sometimes both hold or both don't.

I also noticed change in transformers behavior after load game on the next day. I don't know if it was caused by building circuits in different part of the base because when I save and load game or even exit game and start again without changes, transformers behavior don't change.

This setup at start works fine. Both transformers didn't hold any charge while powering batteries and pumps.

The same setup after few days. I didn't touch it but build different test building that aren't connected with this.
Both transformers keep 200J while transferring power.

The same setup. I just deconstructed wires to the top consumers. First transformer stop holding charge but second still do it.

Once again I build wires for top consumers. First transformer still don't hold charge.

I deconstructed and rebuilt second transformers and wires to the pumps. Now first transformer start holding charge and second one don't do it.

And screen from my main colony when transformers hold charges and with different values (3 top rows of generators are not working at that moment and that's why transformers holds nothing).