Bug: Incorrect fermentability for mash temp >70C

[Brewer #49964]

There is a discontinuity in the predicted FG at 70.0C. Below this temperature the predicted FG seems reasonable, but above 70C the predicted FG drops and stays constant.

The specific values will ofcourse depend on the recipe, but I get the same discontinuity at 70C with all the recipies I have tried.

Mash temp deg C, Predicted FG, Predicted alc. vol %
63.0 1.011 5.21
63.5 1.011 5.25
64.0 1.011 5.27
64.5 1.011 5.28
65.0 1.011 5.28
65.5 1.011 5.28
66.0 1.011 5.26
66.5 1.011 5.23
67.0 1.012 5.19
67.5 1.012 5.14
68.0 1.012 5.08
68.5 1.012 5.01
69.0 1.013 4.94
69.5 1.014 4.86
70.0 1.015 4.77
70.5 1.012 5.13
71.0 1.012 5.13
71.5 1.012 5.13
72.0 1.012 5.13
72.5 1.012 5.13
73.0 1.012 5.13
73.5 1.012 5.13
74.0 1.012 5.13
74.5 1.012 5.13
75.0 1.012 5.13