Json5 error with SimpleCart price field

I have a very strange error with SimpleCart. When I enter a price of 1000 or more then the productlist goes empty in the backend. Until 999.99 there’s no problem.

I then have to manually adjust or delete the record in the mysql database to make the list back visible.

In the Modx error log I get the error “…core/model/modx/modprocessor.class.php : 268) Processor failed creating output array due to JSON error 5”

Any idea?

Latest version of SimpleCart (2.8.0) and Modx 2.8.3. PHP-version 7.4.

Note to future self, this was also sent to support in ticket 29288 and discussed further there. Also created an issue to make the json generation more forgiving in MODX3.