[SR-Users] Inconsistent string interpolation

Hello, I'm occasionally running into issues with inconsistent string interpolation in the kamailio.cfg. Here's the latest example. Take this line: $var(x) = "sip:+$var(abc)-$var(def)-$si@$Ri:$Rp"; Here, the values of the variables will NOT be interpolated into the string. Instead, I have to use this: $var(x) = "sip:+" + $var(abc) + "-" + $var(def) + "-" + $si + "@" + $Ri + ":" + $Rp; However, when I have an instruction such as: append_hf("P-Asserted-Identity: $var(x)\r\n"); Then string interpolation takes place (i.e. the value of $var(x) is put into the string. This is very confusing and error prone. Is it something that can be fixed? The behaviour should be consistent. -Sven