If you have a lot of notifications and leave them to get to at a later time, I've noticed several times now that the choices that you pick whether it'd be accept/discard, join/decline, sometimes do not get picked. For example, if I have a accept/discard and a join/decline offers up, and I'm currently discarding a lot of things, I've noticed that the decline button will sometimes get pressed even though I'm not pressing it, I'm pressing accept. I'm not sure if this is due to radegast needing to load up the next thing to be acted on, or if it is something on SL's servers, but I've seen this happen multiple times now with group invites,teleport requests and other things.
Get a lot of notifications. Start picking the choices you want. Sometimes I've seen that the choice that I have picked doesn't get picked. If I have a lot of things to discard and a join or decline request, I've noticed that the decline button will get pressed even though I've told it to accept. I've seen this with accepting things as well. I'm wondering if screenreaders pick up the new items dialogue box before it comes up visually.