Elm Tribulations

I got the limbs heat treated and the horn nocks done, which narrowed the tips and got the string line just right. Back on the tiller with it and I'm pulling to about 50-60- and the tiller looked horrid the left (lower) limb looked weak just right of centre. I was videoing at the time so you can see it, and hear what I thought.
https://youtu.be/0d1M4mHTpiw

I took it down from the tiller checked everything and it was the right way round ( I had wondered if I had some how reversed it!).
I did a little work to ease off the right limb and get the outers moving more... back on the tiller, looking much better.
Tidying it up some more I noticed a thin little sliver on one edge (about as thick as my thumb nail) had buckled up on the belly, there was a tiny knot on the edge of the bow there where it had started. I squirted some low viscosity super glue in under the sliver, unstrung the bow and bound it tight with rubber strapping while the glue set.
That fixed the problem nicely, I tidied the edge up put it back on the tiller, all was well, until I was again looking at the belly in that area. There seemed to be a blob of glue, or was it buckled wood? Yes, a thin area of the belly was buckling at that point. I was surprised as the bow is relatively low stressed being wide and thin. Had I overdone the heat treating? Was there an existing crack?
Only one way to proceed sensibly and that is to rasp out the area, (including the previous sliver and knot) and have a look.

Yes there is evidence of a crack, a faint line still visible in the rasped out area (running from about 2.5" to the 4" mark on the tape.

Final pic shows the prepared patch (heat treated) lying on the limb to check the fit.

Now this is just my opinion of the cause:- I think there was an existing split/crack /weak point caused when the stave was split.
IMO it shows the value of sawing rather than splitting wood where possible. Personally I'd rather harvest my own wood, but of course we aren't all fortunate enough to have access to every species of timber in profusion! Doubtless the man surrounded by Osage hankers after some  Yew and vice versa :-)
Some wood splits very clean, but even the with the most cooperative wood there will be tear outs and cracks that are generated by the splitting. This stave was pretty thin in the first place (hence the need to build up the belly at the grip)... was the split lurking there, waiting to annoy a bowyer or did it spontaneously spring into being?

In the top two pics you can just see the tiny knot on the top edge where the first sliver buckled up.

I'll update tomorrow when the glue has cured...