Where are my sent text messages?

[AC Question]

I can only see "old" sent messages in the stock messaging app, no third pary apps. When I install a third party app (Chomp, Textra, Android Messages), my current or old sent messages do not display in conversation. New sent messages do. I have searched everywhere for an answer, but no help. Importing/exporting, default app, clear cache, etc. I can even see the sent messages in the phone message log, but not third party apps.

Samsung S6
Android 6.0.1 Stock