Hmmm, it seems the modern way for autocracies to deal with elections is to control the information space. I don’t see election being called off, but major social media platforms boosting one side while attenuating the other goes a long way. We know Musk is all in on this and the other big players like Zuckerberg & Co seem all too happy to oblige. Tiktok is an open ended question at this point.
A lot of software is reliant on very precise timing. The world at large would notice immediately due to the many disconnects, glitches, bugs, desyncs, not to say anything of all the physical processes controlled by machines going wrong. As a simple example consider an industrial oven (or any process really) that is programmed to shut down at 4:39:20 but at 4:39:15 the 1 minute skip happens. An airplanes auto pilot that is suddenly missing the last minute of sensor data to. base its micro steering on. Any big internet service that has to deal with thousands to millions of clients trying to reconnect at once because their previous connection timed out. Bad stuff.
This would be immediate world wide chaos and likely panic as the cause for all the chaos would be unknown and forever would be. Economic crash likely.
Think of all the attention and effort the year 2k problem got, but this one is worse and there is no prep whatsoever.