This has been happening for a while.
I use my mouse in left handed mode, with primary mouse button on the right side through the change your mouse settings window in windows 10.
Whenever this is activated I get some weird doubling of inputs in the game. It seems to be registering both left and right mouse buttons simultaneously. I assume theres some absolute value set in your mouse input or something.
Thank you for your report!
However, this issue has been closed as a Duplicate of MCPE-23383.
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