Lacks 's' extension ?!

My logs are full of these warnings:

WARNING[12169] app_macro.c: Context ‘macro-dialout-trunk-predial-hook’ for macro ‘dialout-trunk-predial-hook’ lacks ‘s’ extension, priority 1

any ideas what they mean? Is it something i should ignore or is there a problem?

recently, we noticed that transferring a call randomly fails and the caller is hanged up during the transfer, maybe this could be the reason?

this is nothing to worry about and has nothing to do with any such issue. Feel free to file a bug about it if you want and we will modify it in the future to remove the warning.