The short answer is I don't know for 100% sure. It's only happened to me once or twice and the rest of the time it's been my wife. The last time for me was maybe 18 months ago, and IIRC I did try to use the memory function and it didn't work either, nor did any of the other seat controls. I'll ask my wife to try the memory function the next time it happens.To add on to the other good suggestions, does the memory function cause the seat to move when the normal adjustment switch does not? That should more or less rule out an issue with the control box. If niether switch causes the relays to click then it sounds more like a bad control box to me as long as the other seat motors work besides just forward and backward. If none of the seat motors work, then it might be a power issue.
The problem is that she loves the truck otherwise, but this issue is causing her not to trust it fully, which has other implications such as her not wanting to drive it.
Come to think of it, I should probably just throw up my hands and maybe she'll insist we go buy a new one. Lol.