Did anyone else eating your Szechuan Peppercorn dish experience the same effect? That would isolate if the problem is specific to you, or something with the spice.
I know table salt enhances your tongue's taste buds to taste sweetness, but I haven't read anything on spices that enhance your ability to taste salt.
Any chance you are experiencing a cold or infection? That can cause taste disorders. https://www.nidcd.nih.gov/health/taste-disorders
Did you recently switch where you get Szechuan Peppercorns from? If so try a different brand. You may discover your current batch is contaminated. If so please file a consumer safety report. In turmeric, lead contamination can make it taste sweet, with a rash of lead contamination reports in the past. https://www.foodsafety.gov/report/problem/index.html
It is normal for Szechuan Peppercorns to cause a confusing sensation in your mouth and tongue. For most people it is a sensation of numbness or having a touch sensation everywhere. https://www.thespruce.com/szechuan-peppercorn-info-694248
I hope you find an answer. Usually with spices the effects are temporary.
In the case of cilantro it was discovered why some people hate it - they have a gene that makes cilantro taste like soap! http://mentalfloss.com/article/91060/why-does-cilantro-taste-soap-some-people