If a scoreboard with the name (not the display name) "$$$" is created, then selectors (@a, @e, @r, @p) using the selector variables score_$$$ and score_$$$_min are treated as player names, not as selectors, by the game.

What I expected to happen was:
The selectors should properly select all the players with the specified minimum or maximum score and execute a command for them.

What actually happened was:
The selectors aren't recognized as selectors; the command interpreter treats them as player names and tries to execute a command with that player name.

Steps to reproduce:
1. Create a scoreboard objective with the name (not display name!) "$$$"
2. Execute a command using a selector variable for that score, for example "/give @a[score_$$$_min=0] minecraft:diamond 1"

I attached two screenshots of the incorrect behaviour and a map to reproduce the issue. On the map, first give yourself some points on "$$$" using the light blue command block, then execute the commands specific to the "$$$" score (the pink and cyan command blocks). I also included an objective "test" for which the issue does not occur.

(I searched thoroughly for this issue before reporting it and haven't found any previous reports, however as it is quite specific, I may have missed one. If that is the case, I apologize.)