Yes! This happened to me this cycle! I started taking EPO and a B complex for the first time. My cycles are like clockwork every month but this was our 5th month of TTC, so I thought I'd try something new. I have textbook 27-29 day cycles. I always get my +OPK on CD 10,11, or 12 and I always feel one-sided cramping when I ovulate.
I had the start of EWCM on CD8 as usual and started my OPKs on CD 9 like always. DH and I BD'd on CD 10,11,12. My OPK lines were practically non-existent all week- very faint. By the time I got to CD 12/13, I stopped the EPO, since I've heard it can delay O and it was clear that I was no where close to O.
I continued taking the B complex, however, until CD 16, when I read that this can also delay O, since it can suppress estrogen. After 48hrs of being off of the B complex, I started getting very mild, generalized cramping (similar to what I get a few days prior to O, as if the follicles are developing). This has continued intermittently (subtle, vague cramping) for the past 3 days or so, but no EWCM and definitely not my usual undeniable, one-sided O cramping. DH and I also BD'd on CD 15 and 19.
My OPKs have not been promising. A couple that I took on CD 18 were about 70% of the way there and I actually thought that they may turn positive the following day or maybe the day after that, but no such luck. I've been taking 2-3 tests per day, holding it for 4 hrs, nothing to drink, etc, so my urine has been quite concentrated. It's now 3 days later and they still haven't progressed and have even gotten a bit lighter. Maybe my body tried to ovulate a week late and was unsuccessful?
Still no EWCM, my boobs are actually starting to feel a bit sore, and my pants feel a little tight, so I think I'm starting my usual pre-AF bloat. The cramping seems to be a bit more noticeable today and similar to my normal luteal phase cramping as AF approaches. Going by my original dates, AF is due in about 6 days, but I honestly don't know whether I'll get my period at all, since everything is screwed up.
I think my body is completely confused. I don't know what to do. I'm scared to death because I've read numerous stories online of other women having similar experiences and having 40, 50, 60 day-long cycles because of this! I'm so upset at myself for messing with my cycle. Now I'm stuck in this period of limbo and I don't know how long to wait or if I should try to induce a period at this point. My body definitely needs to re-set itself and the wait is killing me. I'm so depressed that DH and I lost an entire month of TTC because of this and the next cycle (whenever it begins) may be affected as well.
I feel so sad right now and I'm hoping someone else might have experience with this.
I read that B6 can delay ovulation somewhere, so I researched it a bit and it definitely can delay it! So when AF arrived this time, I went off the B-complex and will resume taking it after ovulation. 
I'm only CD10 though, so I dunno yet if going off it has helped me ovulate earlier or not! Fingers crossed though
