This is the opportunity leading up to the Jean Necteux Keystone. I have to collect 5 Cerambyx beetles in France and then go to Egypt. The problem is when I return home after collecting the beetles they are not in my inventory and the opportunity is gone. This is really getting frustrating because it happens every time. I realize I can cheat to get into the tomb but I just want to get the quest so I can get the Nectar Recipe. Any help would be appreciated.

Im going to answer my own question (for people who also need the answer). I installed Tallan's Traveler and now the quest works just fine. I traveled home with the opportunity still active and the beetles in my inventory :D

Isn't it amazing how many parts of this game EA managed to break?

Yes it is. My latest issue is the fact that I used zeneport and opened the tomb with the recipe too early, so I cant get it lol. Since EA made it so you cant open them again I had to reset France...

Just for the record, until yesterday I was stuck with the "To Egypt!" adventure, too, and this is how I fixed it:
At first it became apparent that the problem was tied to one Sim in my household. No matter what I did, as soon as he arrived in Egypt - with the beetles in his backpack - the adventure did either not update and said that I should return to France to continue this adventure or was dropped completely.

What I did then was assign this adventure to another household member with the help of twallan's DebugEnabler (AwesomeMod's debuginteractions would do the same) while in France.
The beetle part is stage 6 within the Necteaux adventure chain. I chose stage 5, where you have to ask the special merchant about the riddle first.
This Sim then carried the adventure successfully over to his homeworld and to Egypt. In Egypt the adventure continues from stages 6a (To Egypt! Seek Assistance) to 11 (To France!) and stage 12 will be triggered as soon as you arrive in France with the required object in your inventory.

The entire point of the Egypt part is to gain the Ruby of Sakhara and what I found out is that you could actually skip that if you've got DebugEnabler or AwesomeMod: When in France assign the Nectaux' adventure part 12 to one of your Sims and the Ruby will appear in its inventory despite not having been to Egypt, thus allowing you to continue the adventure without the hassles of the desert.

I 've had trouble too!

Me too
I will just try to add "To Egypt" adventure by MC and see if that works.