Just out of curiosity : is also your 2000X HD behaving in the same way ?
I didn't notice anything like that at the time, but I can check it at work with an SDS2104Xplus (I no longer have the 2504X HD).
SDS800X HD Math fuctions update rate slows down when any activity by mouse or touch and same happen also in SDS2000X HD and SDS3000X HD (and big SDS800X HD aka SDS1000X HD but tested only using old version 1)
After touch or mouse activity end, normal speed is returned after around 1-2 second.
Imho, this is a feature. For now. Whether it can be optimized / improved somehow, remains to be seen. Of course it is nice if there is way to do it so that is works independently.
At least in my case, this feature has never made it difficult to use the machines for their intended purpose as a tool. I classify it mostly as a cosmetic "disadvantage" for now.
Of course, I don't use a mouse like in some games maybe by waving it more or less all the time. I only touch it when it is necessary and only for that time. Instead, if the mouse is in hand contact all the time, that way of using it might keep it active all the time and drop the math update speed almost constantly.