The old Avenue Turn Lanes (ATL) plugin has been the source of some issues . . . usually, people having it installed, then not reinstalling it with a new version of the NAM (it isn't a default option anymore, since it tends to interfere pretty heavily with some features), but that leads to blank tiles/no textures where the intersection and approach should be.
Usually, a brief freeze while building a transit network setup means that the path files are absent. I do also notice you have a bit different textures on there. I'm wondering if perhaps somehow you have the INRUL files for the ATL installed from a previous NAM (they were actually in a separate file in an "INRUL Overrides" folder between NAM 32 and NAM 36), plus the textures in a Euro texture file, but not the ATL file itself, which would contain the paths.
We normally recommend now that users completely move/remove the Network Addon Mod folder (and z___NAM, if still present from a NAM 31-36 installation) out of Plugins when installing a new version, since the new installer can't detect what you had installed before. Moving/removing the old folder(s) should normally eliminate any holdovers from the old file architecture.
I'd recommend taking a look to see if you have that INRUL Overrides folder within Plugins\Network Addon Mod. If you do, pull it out, and if you'd like to have the old ATL plugin installed, make sure to check the "Legacy Auto Avenue Turn Lanes" box under 2_Additional Network Features > Road, One-Way Road and Avenue.
Another less likely possibility is some sort of otherwise correct installation that got glitched. The new setup for the ATL has it in a subfolder of 2_Additional Network Features\Road, One-Way Road, and Avenue, called "Legacy Auto Avenue Turn Lanes", and it should have two files within it . . . NetworkAddonMod_TurningLanes_Avenues_Plugin.dat and NetworkAddonMod_TurningLanes_Avenues_Plugin_INRULs.dat.
-Alex