InDesign 2019 14.0.2 has created a new bug with GREP. If you search for any character, InDesign jumps half way through the file.
So, for example, if you click the cursor at the start of the document, instead of GREP finding the very first character that you search for, it instead jumps towards the end of the document.
So, for example, if you do a search for the letter 'a' in GREP, it will miss most of the document out and find the first one towards the end of the document.
To confirm this, if you do a search and replace of . to $0 instead of finding all the characters in the document and replacing them with themselves (we use this for finding out how many characters are in a document), in one of our documents it found and replaced 30,000 characters when it should have replaced 500,000 characters.
This has only happened in this latest update.
Based on user response, closing this issue.
Adobe InDesign team