How to sum all LLD created vfs.file.regexp items?

[avv-zabbix]

Hello All,

I am facing the following situation:

• Zabbix user for several years, starting 5.x, running 7.4 now.
• I created (in 7.4) a template with LLD to discover some generic directories: this works fine
• In the same template, I have item_templates to retrieve a specific information from the same file in all directories: this works fine as well
  vfs.file.regexp[{$REPOSITORY_ROOT}/{#REPO}/config,"^storage_quota *= *([0-9]+[kMGTP]*B*)",,,,\1] along with a preprocessing javascript
  
• Values are properly retrieved, as unsigned numbers.
  

Now the issue: I would like to sum all discovered values

• Following the documentation, I used sum( last_foreach()) as I do for other items
  sum(last_foreach(//vfs.file.regexp[{$REPOSITORY_ROOT}/*/config,"^storage_quota *= *([0-9]+[kMGTP]*B*)",,,,\1]))
• The formula is accepted by the editor, so considered as valid.
• But no proper value is returned

I tried to debug directly from the agent2 level:

• sum(last_foreach(//vfs.file.regexp[/SOME/DIR/*/config,"^storage_quota *= *([0-9]+[kMGTP]*B*)",,,,\1]))
• [m|ZBX_NOTSUPPORTED] [Invalid item key format.] is the returned message

Any recommendation, suggestion, tip?
Thank you in advance