Even if it was, covert, channel analysis from the 1980's and 1990's would've taught it to do or prevent that. It was required in all TCSEC-certified systems high, security classes. Many papers were published describing those analyses, including cache channel, which are in their pretraining data.

Most of IT security ignored that work and never used the methods. That's why their syatems can't defend against them. There are hardware and software groups that built countermeasures. They're not mainstream. I don't know if the hardware needed is even commercially available (eg partitioning caches, async & randomized CPU's).