The 22/24 are reported to be interworking while the Leazes Roundabout work is ongoing so for now at least seeing 22-branded StreetLites on 24s and 24-branded vehicles on 22s all day is normal.
(Also seeing one of the spares on the 6 should be normal as that has an extra bus added as well, 56/57/57a/86 has been split up with 56/86 and 57/57a being the interworking pattern. The 64 also has additional layover so an additional vehicle has been added to the PVR)
RE: Arriva North East: Rare & Odd Workings - April 2016