My auto pickup range keeps getting reset back to normal even when I have the box checked to use my reach distance as the pick up range. some times it's mid play, sometimes it's on armor change, and sometimes it's when I load a save. I wanna be able to pick up items all around me, not just what's at the character's feet, and the problem also extends to the normal pick up when holding the pick up key for sweeping things up.

Seconding this with Factorio 2.1.9.
I have the same bug as you when I'm loading my save.
This mod is also conflicting with reach mods like "Far Reach" because even Far Reach can't increase my reach distance if RPG System is also enabled.

I've fixed this issue on my side; it's just a matter of an "end" instruction that was simply misplaced.

For anyone wanting the solution while waiting for the mod author to fix it:
1- Unzip "..\AppData\Roaming\Factorio\mods\RPGsystem_2.1.1.zip",
2- Open "control.lua" preferably with a text editor like Notepad++,
3- Find the "LevelUPPlayer" function at line 1019,
4- In the function, locate the code block which starts with "if btname=='btLVU_global.personalxp.LV_Reach_Dist' then",
5- In the four lines right below, notice the "end" word at the end of the fourth line,
6- Move this "end" word to one line below and remove one tabulation to align the "end" word to the "if" word from above.

EDIT: Welp, the issue returns when reloading the save, so no solution for now.