If they seal you are good- Sometimes I found that I have to handle jars very carefully. If I set them down a little to hard or tip them sometimes they will suddenly expel a lot of what ever is in them. You don't have to move them very aggressively at all - sometimes just lifting jars makes it happen or like if mentioned above taking the lid off a little too soon can do it too. Tipping the top weight to make the pressure go down faster will do it too.
I went to canning liquids in the evening and when I get to the end I just shut off the stove and go to bed. I leave them in the canner all night and in the morning all are sealed and cooled off. I'm pretty impatient ... this works for me so I don't try to do two batches when I only have time for one. Just did 14 quarts of chicken and this is how I did it.
You can re-process them- it won't hurt anything

Maybe lids to tight. But 15lbs is to much for your elevation. I would remove all lids clean jar edges with white vinegar with new lids and re process at 10lbs.

I agree with Ohio wolverine. Removed pressure to soon. Re process at 10lbs

I've done just about everything you can do wrong while canning and never had this happen. Seems like, you might have some bad lids?

I bet the lids are fine. If liquid is coming out (likely due to releasing canner pressure too soon), then I would think the grease that rises to the top of the broth is coming out along with the broth, getting between the lids and the jars, and preventing the lids from sealing. I suppose try to take off as much of the grease that comes to the top when you are heating up the broth before actually putting it into the jars. I've never canned meat broth, so no actual experience with that.

Using 15 lbs of pressure MIGHT be more than your elevation requires, but it still won't hurt a thing. It will just make the processing temperature somewhat higher. If your elevation is higher than the highest elevation for 10 lbs, then you must use 15 lbs on a weighted guage, to ensure killing any botulism or other nasties that might be in the food being canned.

With a dial gauge and a weight gauge both, you'll have better control of your canning.
I tried the three way weight gauge, and at 10 pounds it's spitting , shaking , and rattling drove me to changing back to my 15 pound weight.
Also once I shut off the heat , it lost pressure very fast.
I had siphoning real bad , IMHO because I'm used to the 15 pound weight, and it's quieter , while holding the pressure longer and releasing it slower.
I will not use the three way weight again.
Already gave them away.

Well, now you know. That's why they siphoned. You need to let the pressure come down to zero on it's own.

Exactly , and the very reason ( one of them anyway) I use both a dial gauge and a weight gauge.
The dial tells me when the pressure is zero, and I still wait about 5 minutes before tipping the weight to see if there's any pressure left.

Did y'all miss his later post where he re-processed, doing everything right, with the same result? I think bad lids.

I’m guessing that grease bubbled up and compromised the seal of the lids.

Possibly it. My guess two possible or both together solutions. Chill the broth until the fat congeals then skim if off before canning or leave more headspace.

While I know there's bad lids out there, even Ball lids are made cheaper than they were20 years ago.
He also stated later that he did remove the rocker to help the tab fall!
Thus causing the jars siphoning .
All three times he missed a step !
IMHO he's getting frustrated , and not following the procedure correctly .