Even ignoring how many VGUs are basically brand new characters... Or the Institute of War getting deleted from existence...
Shyvana's dragon papa got retconned out of existence for no clear reason and I am *still* annoyed about that.
The Darkin went - within the span of a few months - from an alien force invading Runeterra to corrupted Ascended trapped within their weapons. Both of these stories were presented *after* the Institute of War retcon. This new explanation also makes the Rune Wars hard to pin down and raises questions about what Nasus was doing, or why nobody remembers the darkin but everyone remembers the Ascended.
Most recently... this one is actually very minor, but it bears bringing up, I think: Lux gets her staff/wand in the new Lux comic, but she also has it in the short story "For Demacia". The story *must* take place before the comic, as it's before she's made a refugee; so... how is that?
These are only a few examples, but I'm sure I'm missing more.
Look, I don't want to sound like I hate League's lore. Cuz I don't. It's the main thing that I still come to these forums for. It's good that most VGUs these days are focused on advancing stories rather than changing them. And I'm ecstatic that Riot has been moving the story forward in ways we haven't seen since the Harrowing.
But we still get retcons that end up just *deleting* entire swathes of the lore. If the story can just *change* to such an extent that entire swathes of the story are no longer possible or entirely change a character at a fundamental level, why should I care?