question about using the apply function

Hi,

Just wondering if there is something I need to use for the apply function in order for it to apply to the entire array results of another rule. I was just isolating an issue that a user found on one of our applications and I think I have narrowed it down to the use of the apply function.

Here's the situation:

If I separate the RCT_getCdmsContactDetails rule (below) on its own, I will get a result with 4 values that are email addresses of users.
When I apply the RCT_getUserByEmail function, only the first and last email addresses get resolved to users.
If I apply the RCT_getUserByEmail function separately to each of the 4 values, it returns the result that I would expect.
So, I guess it has something to do with how the apply function is being used.

apply(rule!RCT_getUserByEmail,
rule!RCT_getCdmsContactDetails(
pv!organizationId,
17
).email
)