How to use conditional basis entity data in write to multiple data store entity

By looking at your code it looks like you have added wrong condition. iT should be like if that variable is null then don't do anything else write to DB like below. Also in both if condition you are checking same variable but writing to different entity. Please try the below code and see if it is working.

= {  

 if(    a!isnullorempty(pv!communityAllocation),   

         null,   

a!entityData(   

         entity: cons!DSE_COMMUNITIES, 

        data: pv!communityAllocation  )

),

    if(    a!isnullorempty(pv!dependencies),   

         null,   

       a!entityData(     

         entity: cons!DSE_DEPENDENCIES,     

         data: pv!dependencies    )  )}

If you don't have anything to write for a particular Entity entry, you will need to set that list item to EMPTY SET ( {} ), because NULL() actually carries a value and will cause the node to error.

This makes some assumptions into the validity of your null checks.  The second null check (for pv!dependencies) seemed backwards so I switched to the opposite rule (since you wouldn't be writing pv!dependencies if it's actually empty).

{
  if(
    a!isNotNullOrEmpty(pv!dependencies),
    {},  /* null, */
    a!entityData(
      entity: cons!DSE_COMMUNITIES,
      data: pv!communityAllocation
    )
  ),
  if(
    a!isNullOrEmpty(pv!dependencies),  /* note, switching the null check rule used here */
    {},    /* null, */
    a!entityData(
      entity: cons!DSE_DEPENDENCIES,
      data: pv!dependencies
    )
  )
}