System Information
Operating system: Win 8.1
Graphics card: GTX 970m

Blender Version
Broken: version: 2.80 (sub 40), branch: blender2.7, commit date: 2019-01-04 21:18, hash: a77b63c56943

Short description of error
After using pose.select_mirror with 'extend' parameter enabled pose._select_mirror with 'extend' parameter disabled (default) works as if that 'extend' parameter is still enabled.

Exact steps for others to reproduce the error
Make two shortcuts for pose.select_mirror as it shown in the picture.

After using Shift+Ctrl+F ('extend' on) default Shift+F ('extend' off) works as if 'extend' parameter is still on. So both shortcuts do the same after that which is incorrect.