Signature spells misbehaving

[mototom]

I don't believe signature spells are working correctly and wanted to see if anyone else agreed.

As an example, as a 5th level sorcerer, HLO shows me all my known spells from 1st to 3rd as an option for the newest signature spell. I can choose any of them. My understanding is that I can choose any 3rd level spell, so I shouldn't be able to choose a 1st or 2nd level spell unless the sorcerer has taken it in their spell repertoire as heightened to 3rd level.

Basically, as it currently works, HLO lets me choose magic missile, shocking grasp, and grim tendrils as my 1st, 2nd, and 3rd level even if they're all in my repertoire as first level spells, leaving me with 3 open 2nd-level and 2 open 3rd-level slots to do whatever I want with.

When I look at the list of options for the signature spell I can choose at 5th level, it should only be showing me spells that are in my repertoire as 3rd level (regardless of the spell's base level). I should have a simple list of 3 spells to choose from, and instead I have a list of 11.

I can manually enforce the rules and only choose things that are 3rd level, but the higher the PC level the more cluttered the signature spell list becomes with spells that should not be an option.