Not repro.

Try some languages, In Mytextarea.com, or web page input box, shift will be sticky
and in system search input box , or Ominibox  , shift key not be sticky

The same in A11y layout;

For Tamil all keyboards, not repro for shift sticky issue in Mytextarea.com or web page input box

I guess the root cause is related to the auto-cap feature.

Yingbing, can you please take a look? Thanks.

Still repro in 72.0.3623.3 11310.0.0 dev-channel kevin test
Google input tools version: 72.0.20181122.222570995

Check this issue again, when disabled/enabled <enable ime service> flag,all keyboards will restore no sticky, but if switch to Chinese (pinyin keyboard) with ctrl+shift+space, then sticky issue repro again, switch to other any keyboard again, all shift key in the keyboard sticky again

Mouse clicking to switch to Pinyin keyboard, this issue also repro ;