Keyboard input delay (5-15 seconds ea.)

Hello,

I've been using MM with great success and as I began experimenting with different themes, I began to notice a input lag in typing. The lag is not present with mouse movement, or even when hitting enter to create new topics/subtopics. It's only when entering text into a topic field.

Since then, I've reverted back to original themes, reset UI options, and upgraded from v2020 to v2021. Most of my colleagues use MM and none have experienced anything like this. I did some quick googling as well as searching the MM website/forums to no avail.

Has anyone experienced this? Anyone aware of a remedy? Having to wait 5-15 seconds every time you need to move to a subtopic truly erodes the organic experience of MM.

Very hopeful that someone here can assist.

EDIT: I don't have any attached files or images in MM, only links.

Thank you!