Yes. This unfortunately happens every so often for me. Last month I had a heck of a time! My cervix was dancing all over the place and my cups (yes I tried all 4 that I own) would not cooperate either. It sucks, but thankfully, it only happens once in a blue moon for me.

Same here!

I find that when that particular problem happens, it's often because my period hasn't actually started, I'm just having some pre-game spotting. But that might just be me!

This happens to me too. I think periodically (har) my vagina gets bored and decides to shift things around, like how you get bored of your living room and move the furniture. It's never so bad that I can't use my cup (a good thing because I only have the one and am a little confused about trying to figure out a good second one), but it definitely affects the fit and feel of my cup.

Want to try my method?
First, double-check your cervix location to make sure it isn't playing hide and seek on you. Insert your cup so the rim is just beyond your pubic bone and allow it to open fully there. Then nudge the base/stem so the opening points toward your cervix (for me that's a healthy nudge rearward) and finally, give the cup a boost as you kegel (clench the PC muscles) it up and into place. Despite what the instructions say, you want the rim to sit (O) around your cervix. And there's no need to spin/rotate your cup because you already know it's open. But if you want to, go on ahead...

On the other hand, every once in a while we all have a cycle during which our cups just refuse to cooperate. Maybe you're just having one of those?

Yeah it comes and goes. Last couple of cycles were fine, the one before that was so bad I just used pads, next cycle will probably be fine. It just struck me this morning that perhaps the problem wasn't just me being unco! I discovered during my initial drama getting used to the thing that I have a wild-roaming cervix. ;>

I've fortunately got a reasonably tried and true method even when things are tricky, it's just annoying because it restricts where/when I can change it (I need to be squatting in the shower; don't ask me why, but just popping a squat on the bathroom floor still doesn't work!).

I get this! So annoying. It's actually the reason I finally bought some cloth pads, for times when the cup just doesn't want to sit right.

usually my cervix is quite cooperative but i noticed something similar when i have sex on the last few lighter days and want to insert the cup again. then my cervix makes a run up where my vagina has a slight curve upwards (and this is quite new to me too as i didn't have those issues before pregnancy) and i practically have to dig in there and literally shove the cup over my cervix, just with clenching my pelvic floor muscles it will end up right next to my cervix on those occasions.