UK Off-Peak Day return ticket with restriction forcing use of specific trains?

Question

I have an Off-Peak Day Return ticket from Hull [HUL] to Leeds [LDS]. When I purchased this ticket through the Northern app, I also reserved seats for both legs.

When I collected the tickets, I was surprised to see that the restriction code TD. The key part of this restriction (as I read it) is "Seat reservations are compulsory." for outward travel, and "Not applicable" for return travel.

Does this mean that I must travel on the reserved train for one or both of the legs (and not on another service)?

Note: I contacted TransPennine Express about this, and they claim this restriction code does not apply to an Off-Peak Day Return, and I am free to use any service. This is one possible answer, preferably with an explanation of to why tickets might have incorrect restriction codes, and some references as to how to tell the restriction can be ignored.

Answer 1

As others noted in the comments, this is clearly an error either in the data or with the machine (though I can't work out exactly where the TD might have come from). I would print out your correspondence with TPE in the very unlikely event you are challenged; this authorisation should be enough to override any (theoretical, since it's completely inconceivable to me that anyone would question this ticket) issues.