System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 451.77

Blender Version
Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: rB0330d1af29c0
Worked: (2.83.6)

Short description of error

If select edge "lasso method" in Edge mode on UV edge split.

See gif.

Exact steps for others to reproduce the error

In UV editor:

• exactly with lasso and edges

clic "Edge mode"

select lasso one edge in UV

drag