I have been using backend web modules to execute wixData operations against large collections (more than 500 items) because the performance is better than in front end code. I have noticed that the console in Developer Tools (I use Chrome) is throwing this error message:
c3p66.js:2 Uncaught (in promise) Error: WebMethod request timed-out after 14 seconds... Did you forget to resolve a promise?
All the of the wixData operations finish, despite this message. I have my own console message that appears when all operations are completed. If I only process a few records, I get my message. If I process a large number of records -- like over 500 -- then my message never shows up because of the timeout error message. Effectively, it means that code following large data operations will never execute.
I imagine that this is prevent "runaway" backend functions, but anyone running large data operations might bump into this. Not sure if this is a bug, or a feature.