Sometime after the broadcast of Percy's Lucky Day came a clip from its succeeding episode, Bill or Ben?.
It saw Connor arriving back at Ulfstead Castle Station and becoming embroiled in a case of mistaken identity, confusing Bill for Ben.
The two tank engine twins made their comebacks in the preceding episode and were voiced by Jonathan Broadbent.
Series 17 of Thomas & Friends airs weekdays in the UK on Channel 5 milkshake! at 7:35am.
Thanks to SteamTeam for the alert.