CBSubs subscription not automatically activated after successful payment

I am experiencing an issue with CBSubs where a paid subscription is not being automatically activated after a successful payment.Environment:

• Joomla (latest 5.4.3)
• CBSubs (latest version)
• PHP 8.2 (HostEurope, only 8.2/8.3 available)
• Community Builder (latest)
• AcyMailing installed (including regacymailing system plugin)

Problem description:A user completes a payment (Stripe / PayPal), and from the user’s perspective the payment appears successful. However:

• The subscription is not properly activated in Community Builder.
• The user does not consistently receive the expected access/permissions tied to the subscription.

When manually saving the user in the backend, the subscription (plan ID 6) gets assigned correctly and the ACL group is updated, which suggests that CBSubs activation logic itself is working in principle. Debug / Error behavior:With debug enabled, the following issues appear extensively:

1. PHP 8.2 deprecation warnings (dynamic properties), e.g.:
   • Creation of dynamic property ... is deprecated
   • affecting multiple AcyMailing classes and plugins:
     • plgSystemRegacymailing
     • subscriberClass, acyuserHelper, filterClass, etc.
     • various AcyMailing plugins (tagsubscription, tagcontent, calltoaction, stats, etc.)
2. Additional warning:
   • explode(): Passing null to parameter #2 ($string) of type string is deprecated
   • in plugins/system/regacymailing/regacymailing.php
3. These messages appear during the CBSubs order and subscription processing flow, including:
   • cbpaidControllerOrder::createSubscriptionsAndPayment
   • cbpaidUsersubscriptionRecord::activate
   • user save events (onBeforeStoreUser, onAfterStoreUser, etc.)

Observations:

• CBSubs does attempt to activate the subscription (seen in stack traces).
• The user and ACL group are correctly updated when saving manually in the backend.
• The issue seems to occur during or immediately after the payment completion workflow.
• The AcyMailing regacymailing plugin is heavily involved in the user save process and produces multiple PHP 8.2 warnings.

Questions:

1. Could the subscription activation failure be related to interruptions in the payment callback / IPN / webhook handling?
2. Is CBSubs sensitive to PHP 8.2 deprecation warnings in third-party plugins during the activation process?
3. Are there known compatibility issues between CBSubs and AcyMailing (especially regacymailing) under PHP 8.2?
4. Is there a recommended way to isolate or bypass third-party plugin interference during subscription activation?

Temporary workaround:

• Manually saving the user in the backend correctly assigns the subscription and ACL group.
• Disabling debug output hides the messages but does not address the root cause.

Any guidance on how to reliably ensure automatic subscription activation after payment would be greatly appreciated.Best regardsJens.
(Written with ChatGPT - sorry...)