keys issue with l-alt + space

[barfingskull]

My key binds are set up so that my sprint key is left alt. Jump is space as usual. However, with this client I can only do one at a time. The vanilla client I can l-alt sprint then jump while sprinting. In the m9 client when I'm sprinting with left-alt I can no longer jump with space.

My OS is Mint 20.1. Thanks!