The postponement does not surprise , and I don't believe there is anything sinister about it. Just management discovering late in the day supply and demand for experienced controllers..
The airport has retained a skeleton ATC unit for a long time, supported by secondments from other airport operators, to keep it's approvals and instrument approach procedures ticking over.
Approach Procedural ratings are rare, and people holding them looking for a job, willing to take a punt on Carlisle are even rarer. Added to that the closure and refurbishment of the airport does not allow for anyone to get any training done..