To reproduce:
1. Create a new project
2. Create 2 scripts
3. Push to collab
4. Open both scripts on any script editor(i.e. MonoDevelop), make and save some changes( Do not turn off script editor)
5. Revert both script changes at the same time( for easier repro)

Expected: scripts will be reverted
Actual: reverting one of the scripts never ends

Workaround: close script editor while reverting

Reproducible: any 5.5 and 5.6
Not reproducible: any 2017.1, 2017.2, 2017.3

Note: reproducible only on windows