I've had this happen off and on since last week and rarely before. Noticed in some new member threads people have mentioned it - they thought they did something wrong.
Reproducibility: Were you able to reproduce this problem consistently?
No
Repro Steps: What steps did you take to reproduce this problem?
n/a, not easily reproducible
Expected: What action did you expect to occur when this bug appeared?
Expected to hit submit and carry on like usual.
Notes: Any additional information that will help us diagnose the issue
n/a
Browser, active browser add-ons, and operating system
Chrome version is 54.0.2840.99
Windows 10 Pro
Google Docs
0.9
Create and edit documents Details
Allow in incognito Enabled Google Docs Offline
1.4
Get things done offline with the Google Docs family of products. Details
Allow in incognito Enabled Google Sheets
1.1
Create and edit spreadsheets Details
Allow in incognito Enabled Google Slides
0.9
Create and edit presentations Details
Allow in incognito Enabled LastPass: Free Password Manager
4.1.33
LastPass, an award-winning password manager, saves your passwords and gives you secure access from every computer and mobile device. DetailsOptions