Why are 1st letters of some words capitalised after I add a ? Or !

[Oursoulsdad]

Galaxy tab s2. Samsung s6 phone.
A few months back on the pad, two games by the same company started converting the first letter of the last word in a sentence when a ? or ! followed. That was all. Today, my s6 started doing the same on one application. Some words don't exhibit this problem.

I have seen other threads but they don't seem to deal precisely with this. Apologies if I missed one.

 

[Mahdi The Great]

Do you have auto-capitalization option in the keyboard settings disabled?!