Cannot insert pretty tracker “metadata” into trackerlist

• Error

When nesting pretty trackers inside a wiki page, the trackerlist for the inside pretty tracker should be able to accept "metadata" from the outside pretty tracker, specially {$f_itemId}, to use as a filtervalue for the inside pretty tracker.

However this results in the following error:
trackerlist: Pretty tracker reference "$f_itemId" could not be replaced in plugin "trackerlist".

This is true with all of the pretty tracker "metadata" such as:
{$f_created}
{$f_status_input}
{$f_status}
{$f_itemId}
{$f_lastmodif}
{$itemoff}
{$tr_offset}

Note that items such as {$f_xx} where xx is the field id and items such as work correctly. The issue seems to be limited to using the pretty tracker "metadata" inside the trackerlist of the inside pretty tracker.

An outline:

Three trackers: one for Movies, one for Actors, and one for Cast using two "Item link" fields to link movies and actors.

Three Pretty Trackers: one for Movies, one for Actors, and one for Cast

Wiki page for "Raiders of the Lost Ark":
- Calls trackerlist using the Pretty Tracker for Movies with page=view to show details for this specific movie such as release date, studio, poster, etc.

Wiki page for "Harrison Ford":
- Calls trackerlist using the Pretty Tracker for Actors with page=view to show details for this specific actor such as birth date, birth place, etc.

Pretty Tracker for Movies:
- Contains a trackerlist using the Pretty Tracker for Cast that should have filterfield="xx" where xx is the Item Link field for the Movies tracker and filtervalue={$f_itemId}

Pretty Tracker for Actors:
- Contains a trackerlist using the Pretty Tracker for Cast that should have filterfield="yy" where yy is the Item Link field for the Actors tracker and filtervalue={$f_itemId}

Using the {$f_itemId} in the Pretty Trackers results in the error:
trackerlist: Pretty tracker reference "$f_itemId" could not be replaced in plugin "trackerlist".

Workaround:

Make both the Cast fields Page Selectors and use either filtervalue={$f_xx} or filtervalue=

It works, but this approach loses the relational benefits of using Item Link. Also, instead of using drop down selectors to select the Movie and Actor for the Cast tracker, the names themselves are required to be typed in, which can be cumbersome and error prone.

Setting "Importance" to 8 based on multiple discussions of nested pretty trackers over the past 7 years:
https://tiki.org/forumthread63281
https://tiki.org/forumthread61654
https://tiki.org/forumthread60207
http://tikiwiki.1073613.n5.nabble.com/Nested-trackerlists-td18465.html

And also this reported bug: https://dev.tiki.org/item5084

Additionally, I believe this simple fix would greatly enhance the possibilities for Mediawiki-type of infoboxes, such as outlined here: https://dev.tiki.org/item1843

Setting "Easy to solve?" to 8 based on the idea that it should be fairly simple to solve since the Pretty Tracker already allows {$f_xx} and etc., it's just a matter of including the "metadata" fields into that group.

This bug has been demonstrated on show2.tiki.org

Please demonstrate your bug on show2.tiki.org