Does not reproduce with LWRP 6.9.1
Reproduces with Universal RP 7.0.1 and up
Does not reproduce with HDRP 6.9.1
Reproduces with HDRP 7.0.1 and up
Repro steps:
1. Use a project with Universal RP or HDRP with the asset installed in graphics settings, and with Terrain Tools package
2. Create a terrain
3. Open window -> terrain toolbox
4. Switch to the Terrain Visualization tab
5. Change the visualization mode to "Altitude Heatmap"

Expected result: the heatmap will be visible in Universal or HDRP
Actual result: the terrain will turn pink (Universal or HDRP 7.0.1) or invisible (HDRP 7.1.6)