Seems to be a bug with some items not having pricing info from Justwatch. Hopefully it corrects itself on the next refresh, otherwise I will need to ask them why the pricing isn’t being included.
Same issue here on Edge browser in Windows 10 PC.
Noticed it several days ago on random titles in my Watchlist.
Tried the “Refresh Watch Now”, but did not seem to correct the issue of missing prices.
Same issue apparent on the Android Trakt app, v1.8.4 (149)