Hi,
in theory it should be.
But as you know, v2.x is not developed and supported anymore.
---
We improve & fix only v3.x.
---
Make backup, update and test.
In many cases it's related with :
1) old version of module used there
2) addon override from template
3) old or too fresh version of JCE (use 2.6.31 !!)
I've did some testing. Even on PB PRO 2.5.4 I can't edit Addon.
Could it be a localhost problem?
Test configuration in Wampserver:
- Akeeba restore from live site
- Joomla 3.8.13 and Joomla 3.9
- PHP 7.0 and PHP 7.1
- Page Builder Pro 2.5.4 and Pro 3.3.4