I've lost a few trophies without playing a game and thus not losing one. Also this is not the end-of-season reset, which is in about 3 days.
I've won a game at 4064 points and got 30 points = 4094 trophies. Then after a break I played a 2v2 game, which does not count towards trophies, and another ladder game:
But instead of 4094 I started at 4047 and won 30 more points, ending up at 4077. This means I lost 47 points without losing a game. Surprisingly, this is the same amount I'd lose with a season reset, but it's still a few days until that happens.
What happened to me here?