[exim] if expansion item inside run item not giving expected…

As I am having an error condition with ${if} items inside ${run} items
I made a simple example:

  warn
    log_message = Sender is ${run{/usr/bin/echo ${if
def:sender_address {$sender_address}}}}

This produces the result:

2024-06-05 11:35:31 failed to expand ACL message "Sender is
${run{/usr/bin/echo ${if def:sender_address {$sender_address}}}}":
Expansion of "${if" from command "/usr/bin/echo ${if
def:sender_address {$sender_address}}" in ${run} expansion failed:
condition name expected, but found ""

Are ${if} items permitted inside ${run} items?

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