Is it affecting all tabs, or only some? If only some, try to isolate and narrow down specifically what elements cause the issue by either removing pieces one by one until it works or from the other direction, wipe everything out and start with a "hello world", and slowly add your pieces back until it breaks again.

Also does defer load make any difference, or is it being used here?

Hello,

Please share screenshots and prpc version for better understanding.

Thanks & Regards,

Durga

Please go through below article and let us know If any of this matches your usecase

https://pdn.pega.com/support-articles/results-are-not-rendering-if-when-rule-present-tabbed-repeat ,check your prpc version here .

https://pdn.pega.com/support-articles/tabs-inside-dynamiccontainer-harness-not-rendered-correctly

https://pdn.pega.com/support-articles/section-rendered-empty

Thanks,

Arun