First, congratz! Your
sense of taste is very high. You can taste tiny amounts of a substance I cannot taste in large amounts. (I can feel PGA, but cannot taste it when drinking it.)
Yes, it will evaporate out, slowly as it is suspended, but it will come out.
Yes, the nicotine will also react to oxygen at the same time which gives a bitter copper flavor to my taste. (I suspect it would taste different to you.)
If you are doing your own TA dilutions, you may want to try just PG and heat. It will be tougher to mix completely, but I suspect it will mix together if the TA and PG is kept fairly warm during mixing. When mixing it is typical to warm the TA before adding it to PGA anyway, so it shouldn't be too much more effort to warm the PG in the same water bath.