I've had 3 rear indicators mist up. I had 2 replaced under warranty and I broke the 3rd with my knee walking around the bike. I replaced that with a cheap chinky one and that's lasted longer than the OEM.
I broke one accidently. I fitted a cheap Chinese one off AliExpress and there's been no issue with it. I've had a second OEM one replaced since fitting it
Looked at the rear left indicator in more detail and concluded that the little rubber plug is facing directly into the driving direction.
That in combination with the use of the panniers and the open rear tire setup causes a lot of water to “tunnel “ out at the back.
When the roads are wet I have the mud on my back even reaching my helmet.
Luckily it hardly rains in the Netherlands
I looked at the design of the Triumph indicators with sequential led setup and they are fully sealed. No rubber plug to keep the water out
Time will tell if I am right