Uhh, if it's in red it doesn't mean it had expired. It's just loading up. You can keep refreshing it until it shows up if you have the patience.
If you so really wanna hunt them EDMs are a good place to search for them, those skill cubes come by so often they fill my inventory space to the brim even with them fully unlocked so I NPCed all of them.
Source : Me, Professional Black Market Scout :^)
Blitz (last one) is Official Agent skill, so it doesn't have Master Skill Cube yet
Help w/ EXP Data!
Help w/ Server Differences!
Warning to new players:
CLOSERS is a game that adjusts several important details in almost every single patch.
So something that may have been true a month ago may not be true now. Check the date before you reply!