Thanks--never would have occurred to me to change KaM to 2.There is a bug in the code somewhere; I have documented it before in these forums. I THINK it started with the Bad_Rovi Travesty, but it is possible it was there prior to them.
Anyway, this bug does not affect all channels/programs, and that is what makes it difficult to find and understand. I record morning and evening news on three different channels, with each 1P set up to "Keep at Most" 1 recording, and MOST OF THESE 1Ps WORK JUST FINE. But there is one broadcast in the morning on one channel that will NOT work properly unless I set the Keep at Most to 2 recordings. When set for just 1, it regularly misses recordings, and the History/To Do list usually shows the reason is because the KaM limit has been reached (this is true even if I delete all existing recordings).
Deleting the last recording after watching it makes no difference - on the 1Ps that work fine, they always work, no matter if I deleted the last one or not. On the few 1Ps that have a problem, they always have the problem unless I set the KaM to some number higher than 1. And I repeat - for me, this problem is NOT specific to a channel, but to a specific program. For example, the morning news on CBS is one that will NOT work with KaM=1, but the following program, CBS This Morning, records just fine with KaM=1. And no, NONE of these recordings are set for "Keep Until I Delete".