The problem is that you have no idea what "next signaling period" and what "lock in" means in this context.
Shortly:
1. It's no lying at all.
2. You should read more.

Now let's clear up the things a little:
For a start, the tweet is probably referring to the percents from this page: https://taproot.watch/miners
Next signaling period will start in some 4-5 days. After that moment the chart from https://taproot.watch/ will have to have the red area under the 90% mark for an entire period of ~2 weeks.
And this will still not mean that Taproot will be active right away. Instead, from that moment it's considered "locked in", meaning that in November 2021 it will become active.

If I didn't explain it well enough, maybe a re-read of https://taproot.watch/about could help.