LH still detected after ovulation

Hi I'm new to glow and wondered if anybody could help? I'm currently on month 4 of ttc. Unfortunately on the first monthly I had 3 positive tests but then a negative 2 days later dr says it was a chemical as I wasn't late for my period. Anyway I'm just wondering if it's normal for FAINT lines to appear on opks 6 days after ovulation? First month using these 😁 some help will be appreciated