Strange Issues in Unreal Engine: George Skaggs

Hello everyone! Today I am going to talk a little about a strange issue I had in Unreal Engine while developing this last week. So, We are working in blueprints of this project right now in order to quickly prototype systems out due to our cut timeline before we have to finish our demo build. I was working on adding a small little sprint system to the game by just toggling a sprint mod and multiplying our movement speed with that sprint mod. However this idea didn't work as expected, so I decided to do something like this:

However, for some reason, this code had cut off the player's movement completely! I decided to undo my changes back to the old blueprint I was using that just put a print string on the started and completed nodes, which was just so that I could tell there was a toggle. But after reverting to that code using Control+Z, the player still could not move! In the end, I had to revert my files in our source control to get the player moving again. Then I added this blueprint back in and it worked perfectly as I expected. The only theory that I can make about what happened that day was that there was a null reference somewhere that I overlooked while trying to get this working. However, the issue has been solved and the player can now sprint around the level freely!