So, with the sorceror, are you not getting the option to pick what spell slot to use, like in my screenshot above of my multiclassed warlock/paladin Wyll? If we can pick which spell slots to use for multiclassed paladin/warlocks but not sorceror/warlocks then I guess in a way that's good news as it suggests there is definitely a bug with the sorceror/warlock multiclass rather than the inability to choose which slots to use being per design.
(Caveat, of course, as stated above my Wyll doesn't yet have paladin and warlock spell slots at the same level, so I'll watch out for that causing a problem.)
