After updated to the newest Indesign 2020, word cut/ hyphenate in Thai language become incorrect.
The fix for this issue is now available in the latest update of InDesign – that is, InDesign 15.0.2.
Please update your InDesign application to get this fix.
Adobe InDesign team
I, and all of my co-workers, also have faced the same issue. Everything about word wrapping in Thai language goes wrong after updated to 2020 version. This never happen in the former versions. I don't understand why this issue is happen. Even if I use Discretionary Line Break to help Indesign to wrap text properly. But It is not productive at all, because I had been forced to read text all over again and to insert Discretionary Line Break to every lines. So please fix it.
PS. In attachment, I attach some of instance that show what is happen. In this instance I use paragraph style that set language to Thai and use world ready single line composer to compose the text.