Missing cover line

Briana • Boy Girl Twins Born July 2018 at 32 Weeks after TTC since June 2015. MFI and APA syndrome. Had 4 IUIs and IVF fresh transfer prior to FET (2 early miscarriages from IUI and fresh transfer)
Has anyone had issues with their cover line not showing on Glow?  Two cycles ago it did the same thing but I get a cover line for Fertility Friend.  I get really dark 2nd line/positive OPKs and get a temp spike so I'm confused.  Any thoughts.
1st 2 pics are September cycle with no Glow cover line and last 2 are for my current cycle with no cover line