This is the second time this has happened to me in two weeks, and never prior to that. I have received two private messages (one last week and another this one). I opened and read the messages to me, then responded. Then, the messages to me from those two members disappeared from my message in box, unlike much older messages I received. I then checked my message out box and couldn't see my response messages either, other than older ones prior to two weeks ago.

I noticed that the first time, so deliberately created a new message to respond to that writer. I mentioned that I didn't think she received my first response. She received the message I wrote the second time (when I "created" a new message to her vs. responding to her message), but she didn't receive my initial response. I obviously did receive her response to my second.

A couple days ago I received the second private message and responded. It seems like the same thing happened, except now I forget who sent me that PM and what they wrote, so I'm unable to create a new (second) response to that member. Her original message no longer appears in my inbox. I assume she never received my initial response. I feel sad about that.