For the sake of any future searchers, the bug is in fact from the space exploration mod. The mod owner is aware of the issue and a temporary fix is to run a command to reset your permission group, as it sometimes gets 'stuck' as some other entity.

Thank you very much for your help! I honestly can't believe how helpful all of you devs are on this team, something everyone should aspire to.

(This may be related to the space exploration mod, however the problem persists even after disabling all mods.)

When I loaded the game today, many of my shortcuts related to pulling things in and out of my inventory stopped working.
This includes:

transferring to and from chest
transferring to ...