Responses are getting very laggy in combat

Franz keeps taking more than a couple of minutes to progress a single response, such as a roll, damage throw, movement, pretty much the entire combat scene is going sluggishly slow that I have to refresh the browser tab to see what response was sent, if any. Franz is losing track of turn order, attack roll results, DC save results, and is even losing entire context over enemies, failing to reference them any further.

My browser tab reports 4.1GB of memory usage, so if there is a memory leak causing this issue, might want to take a look into it.