Oh very normal yes. Many factors can influence how we taste wine in different settings. Our own physical condition (including what foods we have eaten recently), the environment, the accompanying food if any, and the wine itself. Wine as a living thing evolves in the bottle and it does go through what can only be described as "dumb periods". I find the more complex the wine the more likely this is to happen. I also see a lot of correlation between this and expected longevity. So much more in a Cab than a Sauv. Blanc for example.

There is bottle variation due to a wine being corked, but not all corked wines are that way because of a bad cork. The TCA is most often transferred to a bottle of wine from a cork tainted with it but it can get in the wine from other sources as well. Not all glass that looks clean actually is. The conditions for bottling are sterile for a reason, but unwanted compounds find their way in from time to time. That said, the average is approximately 3% of all wine bottles being corked. So if you are at a tasting and up to fully half of them (1 of the two or more bottles opened as suggested) are corked, that would be an extraordinarily high level of bad wine and stratospherically above the norm. I have never been to a tasting with that high an incidence of variation. In the absence of TCA any variation in the wine from bottle to bottle (all things being equal) is likely due to variations in storage. This is can be a major cause of variations in the evolution of an older wine.