Using Ubuntu 20.04.4 LTS and micrcontroller with ROS2 Foxy, I am publishing an occupancy grid to the topic "/map". Occasionally (does not happen on every launch), the Nav2 Static Layer map subscription with transient local durability does not receive the map. But using "ros2 topic echo --qos-profile servicesdefault --qos-durability transientlocal /map" I am able to view the message. Additionally, if I publish to the "/map" topic from command line when the static layer did not get map, then the map is received. Looking at the topic info, I can see both the subscriber and publisher.

ros2 topic info /map --verbose Type: nav_msgs/msg/OccupancyGrid

Publisher count: 1

Node name: geofence Node namespace: / Topic type: navmsgs/msg/OccupancyGrid Endpoint type: PUBLISHER GID: 01.0f.13.11.64.3b.b0.8a.01.00.00.00.00.00.17.03.00.00.00.00.00.00.00.00 QoS profile: Reliability: RMWQOSPOLICYRELIABILITYRELIABLE Durability: RMWQOSPOLICYDURABILITYTRANSIENTLOCAL Lifespan: 2147483651294967295 nanoseconds Deadline: 2147483651294967295 nanoseconds Liveliness: RMWQOSPOLICYLIVELINESSAUTOMATIC Liveliness lease duration: 2147483651294967295 nanoseconds

Subscription count: 1

Node name: globalcostmap Node namespace: /globalcostmap Topic type: navmsgs/msg/OccupancyGrid Endpoint type: SUBSCRIPTION GID: 01.0f.13.11.69.3b.82.db.01.00.00.00.00.00.6c.04.00.00.00.00.00.00.00.00 QoS profile: Reliability: RMWQOSPOLICYRELIABILITYRELIABLE Durability: RMWQOSPOLICYDURABILITYTRANSIENTLOCAL Lifespan: 2147483651294967295 nanoseconds Deadline: 2147483651294967295 nanoseconds Liveliness: RMWQOSPOLICYLIVELINESSAUTOMATIC Liveliness lease duration: 2147483651294967295 nanoseconds