I recall this being the case A LOOOONG time ago but I haven't heard of, read about, been warned to look out for or personally seen such a thing in forever. Have you?
* I'm running a lot of MySQL stuff and such a topic might be of interest to me
Yes, it is messy when you want your MySQL databases to be mission critical in production, e.g. handling a large amount of customer data. Historically MySQL's High Availability architecture has a lot of design and implementation issues because it was an afterthought. Dealing with large amount of critical data means you need it to be performant, reliable and available at the same time, which is hard and requires you to deal with caching, sharding, replication, network issues, zone/resource planning, failovers, leader elections and semi-sync bugs, corrupted logs, manually fixing bad queries that killed the database, data migration, version upgrades, etc. There is a reason why big corps like Google/Meta has dedicated teams of experts (like people who actually wrote the HA features) to maintain their mission critical MySQL deployments.
From what I can tell, MySQL is supposed to be safe since 2018 if you have no data from before 2010.
The fact that you still can't use DDL in transactions makes life exceedingly painful, but it's technically safe if you write your migration code carefully enough.
Some places still have columns declared as utf8 instead of utf8mb4, and there's a special place in hell for authors of the MySQL general clusterfuck regarding encodings - it was all nice and great if you didn't care about anything other than latin1 or ASCII - go outside that before utf8 option and it was horror that even experienced operators managed to fuckup (I have a badge from a Google conference in 2017 with nicely visible effect of "we have mixed up one of the three separate encoding settings in MySQL and now you have mojibake in your badge").
And then there's UTF8 not actually being UTF8, which can result in total lockup of a table if someone inputs a character that does not fit in UCS-2 and now you need to recover the database from backup and preferably convert all instances of utf8 to utf8mb4, because fuck you that's why.
In fairness, reasoning about collations is like peering into the abyss. I get why they’re required to have so many levels of detail, and the Unicode Consortium has done a fantastic job, but to say they’re complicated is putting it mildly.
Oracle also didn't support Boolean data types for a long time, and had a 20 some odd year public thread arguing that no one needed a Boolean data type (https://asktom.oracle.com/ords/f?p=100:11:0::::P11_QUESTION_...). They finally added it in Oracle 23 which is nice, but I wouldn't consider it to be in good company to be lacking something Oracle also lacks.
Not having a boolean data type is IMHO just an annoyance, not comparable to the lack of transactional DDL.
But to the point, people often use this point to claim that MySQL is a toy database, not usable for real world production use. I use Oracle as a counterpoint, which also has a lot of warts but is pretty much an archetype of an enterprise-grade DB engine.
* I'm running a lot of MySQL stuff and such a topic might be of interest to me