[Help] When run, drain SP, when not running, regen SP, when drained, disable run, However if fully drained, it no longer wants to regen :( Options

[Taiine]

So. I have a small issue with a Common Event that helps control running.

In my game, SP is energy, used for normal special attacks as well as running. However my running event has a little quirk.
So, you can run, and it drains the players SP, you stop or walk, and it slowly regens. If it becomes fully drained, the players run key is disabled, so you are forced to walk it until you regen enough to run again. However, once drained, the SP appears unable to regen at all.

I'm unsure what is causing it to stop regening when your SP becomes fully drained. I have the players SP set to a variable, and set so if the var is <= 3 disable running, else, enable it. I have another event in game that simply tells me what the variable is currently at (roughly telling me how much SP I have to debunk this) and yes, it does indeed go up and down as I run and stop... However, once drained, the variable becomes stuck at 3. Use a potion to restore SP? The variable is still stuck at 3.

[Show/Hide] my common event

The part highlighted in yellow is the prob. If I remove that, the players SP can be fully drained, but still regen when you stop... however with nothing to disable the running, well the system becomes rather pointless.
There is nothing in the branch telling SP to not regen once it hits 3 or below. Just to disable running key so you can't run (and that is in no way alone tied to the SP)

I tried this making the event a parallel as well as what you see, the SP just wont regen once drained, and I am boggled as to why.