If a command has invalid syntax, exception

com.mojang.brigadier.exceptions.CommandSyntaxException

can be logged. This can be a problem if the command is in a repeating command block. This causes the same error to repeatedly get logged, making the log file gradually get larger.

Example command:

/tellraw @p {"text":"a","hoverEvent":{"action":"show_item","value":"{id:stone"}} 

A similar report is MC-121913
With this report it was more of an issue because it was made around 1.13 when many commands changed, likely leading to many syntax errors.

But nonetheless my report seems to be similar at least in regards to the potential for a huge log file if the problem is not noticed.