Dear Troubled of Tunbridge Wells
I can assure you it's not a conspiracy. Or at any rate, it's not a conspiracy to which yours truly is a party. I fell foul of the very same problem in yesterday's puzzles, getting "care" in one of them, but forgetting to put it in on the other one! ["You should take more care," I hear someone saying.]
Depending on your world view, it's either sheer coincidence, or spooky synchronicity.
But I lean towards the idea that something ought to be done about it. That is, the puzzle-generation process could be modified to guard against too much overlap of letters, or at least make it much less likely to occur.
When this issue came up before, I think someone said to leave things as they are - it's all part of the challenge, but I'm still not totally convinced. Any other thoughts?