Model Errors in FlashPrint

I just found CookieCad and i’ve been playing with creating some shapes for polymer clay. I have a FlashForge Adventurer 3 and haven’t had too many issues slicing with FlashPrint, but for some reason, when I upload new STL files from CookieCad, I get an error message and have to have the program “repair” the models. Does anyone else have this issue? I have been able to print models that come up with errors and have been repaired in the past, but I’d like to avoid that all together.

I’m new, too. I have had this pop up in every model I try to print. I just selected “Repair Model” and everything seemed to work just fine.