PHP 7.3 not creating/writing to error log file

I have just upgraded to PHP 7.3 (using XAMPP) and for some reason it seems it is not writing errors to the specified log file.

I am getting deprecated errors on page output, but they don't seem to be showing up in any log file - which is more ideal since the errors aren't always visible in the page display, they get hidden in the code if they are generated between attribute values for example.

In my php.ini I have:

error_reporting = E_ALL
display_errors=On
display_startup_errors=On
log_errors=On
log_errors_max_len = 2048
ignore_repeated_errors=Off
ignore_repeated_source=Off
report_memleaks=On
report_memleaks=On
html_errors=On
error_log="C:\xampp\php\logs\php_error_log"

Edit: I just noticed today the file was created recently and it had other errors in there (ones generated from issues in php.ini itself such as deprecated settings about track_errors), but still not getting anything logged about issues caused by pages themselves.

Why am I not getting errors logged from pages?

from PHP 7.3 not creating/writing to error log file