I was up on the roof today, so I had a look too see how it was holding up so far. The tape on the aerial connector was exactly as the day I applied it:

But the tape on the amp connectors has spit and deformed:

What happened? The amp connectors are semi-enclosed, so I would have expected them to be fine. The aerial connector is completely exposed to UV etc., and it's perfect.
The F-Type connectors were loaded with silicone grease, and I thought the tape might have reacted with that, but the F-Type connector used for the aerial was exactly the same...