To reproduce:
1. Open any project
2. Create a cube, add cloth component
3. Scroll the Inspector window, or hover on different windows and back

Expected: console prints out one warning message
Actual: console keeps printing out 2-4 warning messages "MeshRenderer will not work with a cloth component!"

Reproduced in: 5.5.4p2, 5.6.2p4, 2017.1.0p1, 2017.2.0b4
Not reproduced in: 5.4.5p4
Regression starts in: 5.5.0a1

Note: earlier, printing is provoked by scroll-wheeling the inspector or using the scroll bar. Since 2017.1.0b1, messages also start printing when hovering on different windows or views
Note: I would suggest printing one warning message on adding cloth component and one each time entering Play mode