Improper display and buttons behavior above 1.94

[alexnikgr]

MPGuino: Original schematics, own build.
Changes to the original: Raystar EH1602A OLED Screen (https://www.raystar-optronics.com/oled-character-display-module/16x2-oled.html)

Short description
When compiling versions >1.94, I get garbled text in the LCD and having issues with navigation.

Longer description:
Using source "2017-OCT-16", text is ok after a cold start. However, menu navigation is not proper with the buttons (cannot reset current, tank via the button combination, MPGuino is entering the setup menu without pressing two buttons). When trying to navigate in menus, after some time text becomes garbled.
Using source "2023-AUG-14", text is garbled from the start and MPGuino is unusable.

Going back to 1.94 "2017-FEB-08" source, everything works smoothly.

[FlashStopFall]

@alexnikgr, I had almost the exact same issues with a full legacy setup (legacy 16x2 lcd). The issue turned out to be a power delivery problem, either a weak power supply or bad connections. After adding more jumper wires across various power and ground points (I was on a breadboard), it worked exactly as it should.

Maybe you have a bad connection, or your display is drawing more power?