Here's a strictly silly suggestion: After one of their slingshot galaxy hops, the crew wakes up to find everything painted pink. Since it wasn't pink when they went to sleep, someone must have done it while they were between galaxies... but who?
Q, being mischievous? Some alien who thinks the crew lacks any sense of interior decorating? Some natural phenomenon that turns everything pink? Some microscopic pink alien life that's coating the entire ship(s)? Let the mystery (and the repainting) begin...
(inspired by lots of "Trading Spaces and "While You Were Out" episodes on TLC