Spotting every cycle 7 days post ovulation

Hey! My hubby and I have been TTC for 8 cycles now (currently in cycle 9) and 6 of the last 8 cycles I have spotted on days 21-23 ish but still no baby. My cycle is 29 days and I have taken ovulation tests and know I’m ovulating normally. I never spotted before we started trying so my assumption is that it has to do with TTC but no one I’ve talked to has experienced this. Have any of you? I know implantation bleeding happens around that time but we haven’t had a single positive pregnancy test. I would love to know I’m not the only person who has experienced this!

Thanks 🤗