Toilet bowl cleaner container distorts flushing action
Step one - does removing the jar solve the problem?
Step two - can the jar be placed differently in the tank, and if so,
does the problem recur?

It's probably not the volume, and it may simply be the case that this type of toilet cleaner is not compatible with the hydraulics of your toilet tank (which can be quite sophisticated in modern low-flush toilets, so adding an obstacle that might not have bothered an old 5 gallons-per-flush toilet may simply no longer be an option - in which case you need to clean the toilet another way...)