Something similar happened to me. I have a note with almost 100k words and it is divided into multiple headings. Most headings have numbered items and the number of the items are really important. I pasted an item with a number in the middle of the note and ALL the numbers from the headings below changed. Fortunately, I quickly noticed and rewrote only the last section from an older version of the file I luckily had on my phone.
Since it is critical, I’ve downgraded to 1.7.7 temporarily. Here’s how to do it for anyone who’s interested.