This can happen when you have a participant step and the account selected does not exist. Hence the "null" part in the message.

Are you able to have a look at the dispatcher source and tell us what are the rules for this behaviour? The dispatcher is like black-box no one seem to want to look at its source.I have a similar question right now I have stat level set at 4 and flush event at level 6 touches all the way to and incl...

You can write a function that accepts a  resource and makes necessary structure under it. Do you want an example? Side note. Also as this is On-Deploy code you can find examples of unit tests in the ACS repo. Other methods you will be shooting blind.

As experience fragment are content you can follow the tenant segmentation:<tenant>/<region>/<language>so your content will look like this/content/<tenant>/<region>/<language> /content/experience-fragments/<tenant>/<region>/<language>/...this will ensure no one is confused where things are and why.

Create an on deploy script and use ACS On-Deploy pattern On-Deploy Scripts (adobe-consulting-services.github.io) I've put sample code and examples here How to add property and author a component programmatically? - AEM.Design

Correct answer to this question is to clear cookies, whatever is marked as "correct" is incorrect.

@yaraslaud208334 I can confirm that only 503 error code will force Dispatcher to return cached page. Rest of the error codes will remove your cached file.  BONUS: If you are using ACS Commons Error Handler and have Throwable.jsp update its reponse status code to 503 to return cached page no matter w...