I have had same issue on CD2 Juniper my lining is always 6-7 and my FS likes it to be around 4. When he scaned me along the cycle it seemed to thin out and looked good on scan (13.4) But different story on blood results. Seemingly I have a follicle that hung around from last month (functioning cyst producing hormones) that measured 29mm (rest were around 15mm) and as this folicle is so far ahead its causing my progesterone levels to rise too early and make my lining too thick too soon (its called premature luteinisation). Im wondering is this guy causing the problem each month with my lining being too thick. I have to freeze embyros and do a frozen cycle whenever my lining behaves it self! And pray we have some to freeze. So worried as we had none 2 freeze last round But good news this morning is we had a great number, 20 eggs 18 mature so should have lots to choose from! That's if my DH very dodgy sperm is good Much better result than last time and this time I took Melatonin, Q 10 weekly acupuncture and herbs. FX for good news at end of week!