Location Referencing tab not appearing

[GraemeBrowning_Aurizon]

My understanding is that for the Location Referencing toolbar to appear in ArcGIS Pro 3.0.3 when using an Enterprise Geodatabase these requirements must be met:

1. Location Referencing must be licensed
2. Map view must be open, and that map must have three layers present that have as their source Feature Service Feature Classes for a network, its centerlines and calibration points 

In an existing project I have a map view open, and I can see the Location Referencing (and Linear Referencing) tab present (as expected).

Into that project I insert a New Map, and into that map I use Add Data to add a layerfile named Route Editing Layers (DEV Portal).lyrx.  As expected, the Location Referencing (and Linear Referencing) tab appears, and I can see the expected network, centerline and calibration point features classes and that their sources are feature service feature classes.  I close that project without saving because it was only a test to prove the layer file does what I think it should.

I restart ArcGIS Pro without a template, and insert a New Map into it.  I use Add Data to add the same layerfile named Route Editing Layers (DEV Portal).lyrx into that map.  This time, the Linear Referencing tab appears but not the Location Referencing tab, even though I can see the expected network, centerline and calibration point features classes and that their sources are feature service feature classes.  

Why might the Location Referencing tab fail to appear in the second test?

If I create a new project using the Map Template, and add the same layerfile into its only map, then the Location Referencing tab fails to appear there too.  I am confident that in the past the second and third tests would have produced the expected result and am at a loss as to why even with several laptop and ArcGIS Pro restarts this problem has emerged and remains.

[AyanPalit]

@GraemeBrowning_Aurizon The pre-conditions stated are correct and once met the Location Referencing ribbon 'should' show. Also, look for the Location Referencing tools under Geoprocessing. If they show with a lock - the license is not available. If the GP tools show, perhaps it is the layer file. You can test by adding the feature services directly. Feel free to log a Tech Support incident if this abnormal behavior continues.

[GraemeBrowning_Aurizon]

@AyanPalit Thank you for those ideas to try, which I did on a project created without a template and inserted a New Map into. 

1. When I looked for the Location Referencing tools under Geoprocessing all are present, not locked and can be opened so the issue does not seem to be license related.
2. When I added the feature services directly the Location Referencing tab still does not appear so the issue does not seem to be the layer file.

I've tried refreshing the portal from the Portals tab of the Project Page and that does not resolve it.

I think the issue must be with one or all of the three feature services.

Something we did recently was to try a variation to copying the LRS from our Production down to Development.  In the past I've always deleted the Feature Layer and Map Image Layer before deleting the old DEV LRS and copy/pasting the PRD LRS, configuring Branch Versionings, and recreating both by using Share As Web Layer.  This time a colleague using his own credentials used the same workflow but only stopped (instead of deleting) the Map Image Layer service and then restarted it at the end.  When I can see the Location Referencing tab I have no problem editing using my own credentials so the only quirk seems to be that these feature services added to a New Map do not enable the Location Referencing toolbar, unless the project has an existing map in which they had already been enabled.

I've not yet logged a Tech Support incident because I'm only working at this site one day this week and one day next week.  Unfortunately, other project demands mean that I won't have time to liaise with Tech Support on any testing that is exploratory rather than focused on what I've found so far.

The two ways that I know and think will allow me to workaround this problem are:

1. Do my work in an existing project that already has the Location Referencing tab enabled - have been doing this for last day or so and it works
2. Delete and recreate my DEV LRS and its feature services using my original (delete services) rather than recent (stop/start services) workflow - not yet tested.

Another bit of software behaviour that seems odd is:

• If I open a project with an open Map view that shows the Location Referencing toolbar and add the feature service feature classes as layers (direct or from layerfile) to a New Map then that has the Location Referencing toolbar
• If I open the same project (not saved after test in above dot point) with an open Map view that shows the Location Referencing toolbar, then I close that Map view before I add the feature service feature classes as layers (direct or from layerfile) to a New Map then that does not have the Location Referencing toolbar.

[AyanPalit]

@GraemeBrowning_Aurizon The process followed to copy LRS between the 2 environments doesn't align with documented process. I tend to agree that the feature service seems to be missing a property, such that Pro cannot detect LRS.