Slim format (3px wide arm) skins becoming 4px wide arm upon closing and reopening the game

Whenever i were to upload a custom skin to the dressing room and set it as slim format (aka arms are 3px wide), it will show as slim format. However when i close the game and reopen it, the skin glitches out and becomes a 4px wide skin. The affected version is 1.21.44 only

Steps to reproduce:

1. Choose a minecraft skin that u made or downloaded
2. set it to slim format
3. close the game then reopen.
4.Go to dressing room and the skin glitches out and becomes 4px arm wide skin