I am still on Sierra and I have about the same amounts of hiccups with 2019.5 as I had with 2018.12. Every few minutes it stops with a four digit error message and some sessions reliably crash PT on quit. Some of the stops are related to graphics like opening some plugin windows. I guess some plugins I use regularly mess with the system- but which ones???
I just (re)did everything in the troubleshooting document to be sure, but that did not help at all.
Do you think I should update to Mojave? I have a compatible graphics card in my 2012 12 core cheese grater. Is there any possible downside to going Mojave, like some plugins still not working?