System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.37

Blender Version
Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-02-12 16:20, hash: rB77d23b0bd76f
Worked: (optional)

Short description of error
loop tools addon dose not respect mirror merge if subdiv is on

Exact steps for others to reproduce the error
1-make an object
2 add mirror modifier
3-add Subdivision modifier (important as without it this bug will not happen)
4- use loop tools addon on mesh in edit mode
5- see that merge gets unchecked in mirror modifier every time you use loop tools (this will not happen without a subdiv modifier)