OPENSHIFT_MYSQL_DB_PROXY_PORT not defined on scalable apps

Issue

Sometimes while creating a scalable app based on a "php-5.3+mysql-5.1", we obtain an empty OPENSHIFT_MYSQL_DB_PORT on php gear(s)

For example when i check mysql port directly via ssh :

>rhc ssh myapp --gears "env | grep MYSQL_DB_PORT"

=== 524ec484bf2db2e965000065 mysql-5.1
OPENSHIFT_MYSQL_DB_PORT=3306
=== 524ec484bf2db2e965000062 php-5.3+haproxy-1.4
OPENSHIFT_MYSQL_DB_PORT=

When I look into mysql gears via ssh I can see that $OPENSHIFT_MYSQL_DB_PROXY_PORT is not defined.

On the node where mysql's gear is hosted I see those logs in /var/log/openshift/node/platform.log :

CLIENT_RESULT: MySQL 5.1 database added.  Please make note of these credentials:
CLIENT_RESULT:        Root User: ...
CLIENT_RESULT:    Root Password: ...
CLIENT_RESULT:    Database Name: myapp
CLIENT_RESULT: Connection URL: mysql://$OPENSHIFT_MYSQL_DB_HOST:$OPENSHIFT_MYSQL_DB_PORT/
CART_PROPERTIES: connection_url=mysql://$OPENSHIFT_MYSQL_DB_HOST:$OPENSHIFT_MYSQL_DB_PORT/
CART_PROPERTIES: username=...
CART_PROPERTIES: password=...
CART_PROPERTIES: database_name=myapp
APP_INFO: Connection URL: mysql://127.0.254.1:3306