After upgrade to ProjectRed-1.10.2-4.8.3.47-integration comparator sometime don't detect block redstone state change (i.e. Red Stringed Comparator), placing redstone on output causes update.

In my testing, the comparator does work on vanilla chests... however it still doesn't update correctly when used on droppers or hoppers as of version 1.16.5-4.11.0-beta.

Can you confirm that this is only happening after that update and was not happening before?

It was happened before. Similar problem:

https://www.reddit.com/r/feedthebeast/comments/6jxqcm/1102_anyone_else_notice_that_project_red/

I have the same issue in 1.12.2 measuring a TE energy cell. Block updates (eg breaking a block or wire next to it) update the comparator. Vanilla comparator works.

This still happens today... and I think it happens to other things as well. These kinds of blocks are a major reason for using ProjectRed so I would think this should be a high priority fix?

Functioning properly in 1.15+. I tested with a vanilla chest. The comparator updates signal strength accordingly when items are added/removed from the chest.