Context based Macro Override on Discovered Items not working in 5.4

[Daniel4711]

Hello all,

I have a template with a discovery rule for determining logical disks on our Windows Server.
This comes from an earlier Zabbix 3.x installation and I would now like to use it under Zabbix 5.4.

The macros are stored in the template:
Example:
{$T_INFO_WARN_SPACE_LOW} - 5G
{$T_INFO_CRITICAL_SPACE_LOW} - 2G

The trigger prototypes look like this:
Name:
Space on {#DISKNUMLET} - Less than {$T_CRIT_FREE_SPACE_LOW:"{#DISKNUMLET}"} free

Problem Expression:
last(/t_task_LogicalHarddrive_Windows/vfs.fs.size[{#DISKNUMLET},free])<={$T_CRIT_FREE_SPACE_LOW:"{#DISKNUMLET}"}

With Zabbix 3.x, I could override the thresholds per host with a context based macro:
Example:
{$T_CRIT_FREE_SPACE_LOW:"C:"} -10G

This doesn't seem to work anymore with Zabbix 5.4 and I don't understand why.
Neither threshold nor name are used despite override at host level.

[Daniel4711]

It's time for the weekend!
It seems a space was missing:
{$T_CRIT_FREE_SPACE_LOW: "C:"} -10G