False heat?

I have a 2nd calf shorthorn cow that I put an embryo in last Saturday so she was standing 7 days prior to that. Then yesterday I let the cows into a new pasture but when I went out today to check on them she was being mounted and standing for about 10 seconds. If it's a true heat it's only 15 days and now I'm not sure if I should try and ai her or wait and see, but I don't want to lose the the embryo if I try and breed her again. Anyone ever dealt with this?

Tuff to say for sure but she my be cystic.  This will require a shot of GnRh to remedy.  However if you spent a lot on the embryo wait and watch her for 21 days at the end of that time a good vet should be able to ultrasound for a pregnancy.  If she comes in again before 21 days give here the GnRh and turn her out with a bull.

We had a registered cow have a real good heat and about a month later had a calf , as well as another heifer who had continued heats and then had a calf.

Just in the last 30 days, I have had TWO females do that. Both were AI'd, then came in again about 8 days later. Neither stuck to either heat, and we used Cystorelin to help if they were cystic.
This time of year is so hard to get them bred, and stuck. I like to get all my breeding done by June 1st, to avoid it.