/xp command with levels seen as a syntax error

Partner Rank:

2

Partner Team Reporting:

Everbloom Studios

Verification builds:

1.16.0.63

Summary:

The /xp command with levels seen as a syntax error. Example:
/xp 5L
/xp 15L
/xp -100L

Impact:

We can't add exact experience levels now, and neither can we remove xp from the player.

Also breaks any map that tries to control the player's experience bar. Example: Firefighter Roleplay. Since the commands are unable to clear the xp when the player refills the truck, the player constantly gets more and more xp.

Another upcoming map of ours also uses the experience bar to convey information to the player and it's useless considering it always goes up and up and never down; even annoying as it plays the levelup sound every few seconds.

Repro Steps:

1. Open a world with cheats on
2. Run /xp 50L

Observed Results:

You get a syntax error in chat and don't gain 50 levels

Expected Results:

You should gain 50 levels

Screenshots/Videos attached: Yes/No

Yes

Regression Builds:

1.16.0.61