I've had similar situations and narrowed each one of them down to certain circumstances that were affecting me, YMMV.
1. The food that I had eaten in the afternoon and then I vaped made the flavor of the vape nearly non existent. I've since learned (through experimentation) that drinking black coffee seems to cleanse my pallet and brings back the flavor and sometimes even enhances it. I now generally make sure that after breakfast and before walking out the front door that I take a last swig of my hot black coffee and swish it around my mouth to cleanse my mouth. Most of the time it works if I'd been eating some of the foods that caused it. I'd love to be able to tell you exactly what foods have caused it for me, but i'm having a total mental block at the moment on what they are plus I now don't usually give it a second thought when it happens, I just order (or make if at home) black coffee to clear my mouth.
2. I have dentures (obviously if you don't have full dentures or partials that need adhesive then it won't affect you) but... There are certain denture adhesives that I've used that seem to block the flavor from when I'm vaping. Nothing I can really do about it other than wait until after dinner and take out my dentures to soak them overnight and then not use that brand and or flavor of adhesive again. Obviously this won't affect non denture wearing people.
It's not like the spicier the food the less flavor in my vaping, it's just some types of food seem to do it to me and once that's cleansed out of my mouth by whatever means the flavor returns to my vaping. Perhaps you happened to hit upon something you ate that caused this?
If I don't cleanse my mouth after some foods, the lack of flavor can go on for hours and hours for me. As I mentioned, for me I find that taking a good sip of hot black coffee seems to bring back the flavor or just let whatever it was that I ate that seems to have caused to eventually wear off on it's own.
