I doubt very much if freezing of the JOINTS (rather than cables) in the cabinet is the cause, as it has not been particularly cold; but keep in mind that water does expand about 10% on freezing, so could disturb joints and that frozen water is crystalline; and most crystals are poor conductors.
I have encountered something like this many years back with the phone system at work.
There had been a really long, very hard frost, going on for weeks and with temperatures well below freezing, even around mid-day.
The phone system started to give problems, tracked down to a poor earth connection outside the building, on an exposed position to the north, just outside the PBX location.
The Works Engineer was contemplating this with some perplexity when I happened to be passing. He explained the situation.
As a temporary solution, I suggested that a few buckets of hot water might provide some relief.
This prove to be the case, working until the earth rod was moved to a more protected situation.
Could it be corroding joints?
Again many years back, noise on my domestic line was tracked down to a small jointing box at footpath level, on the circuitous way back to the cabinet. (The cabinet is about 30 yards in a direct line; but the cable run via this jointing box, is about 150 yards!)
The GPO/BT engineer remade the "wrapped joints" on my line, curing the problem. He had already done so in the cabinet, to no avail.
The jointing box was a metal casting, about 1 foot (30 cms) high, 2 inches (5 cms) wide, and front to back, with, I think, GPO TELEPHONES cast in relief vertically on the main face.
I have seen similar boxes used in local electricity supply lines, with the appropriate name/initials on that face.