Pymc3 evaluates function but doesn't update sample

A bit more info. When I print out the values of the parameters that are run when samples aren’t updating this is the output:

lambda __str__ = 55.0
mu __str__ = 55.0
sigy_K __str__ = 250.0
mod_K __str__ = 50.0
sigy_H __str__ = 250.0
mod_H __str__ = 50.0
55.0 55.0 [   1.  250.   50.] [   1.  250.   50.] 100

Auto-assigning NUTS sampler...
Initializing NUTS using jitter+adapt_diag...
Initializing NUTS failed. Falling back to elementwise auto-assignment.
Assigned Slice to lambda_interval__
Assigned Slice to mu_interval__
Assigned Slice to sigy_K_interval__
Assigned Slice to mod_K_interval__
Assigned Slice to sigy_H_interval__
Assigned Slice to mod_H_interval__
Assigned NUTS to sigma_log__
  0%|                                                                                            | 0/2 [00:00<?, ?it/s]

55.0 55.0 [   1.  250.   50.] [   1.  250.   50.] 100
55.0 55.0 [   1.  250.   50.] [   1.          250.           42.89492834] 100
55.0 55.0 [   1.  250.   50.] [   1.          250.           21.65069853] 100
55.0 55.0 [   1.  250.   50.] [   1.          250.            9.22774195] 100
55.0 55.0 [   1.  250.   50.] [   1.          250.            3.60497646] 100
55.0 55.0 [   1.  250.   50.] [   1.          250.            1.35712256] 100
55.0 55.0 [   1.  250.   50.] [   1.         250.           0.5035775] 100
55.0 55.0 [   1.  250.   50.] [  1.00000000e+00   2.50000000e+02   1.85847404e-01] 100
55.0 55.0 [   1.  250.   50.] [  1.00000000e+00   2.50000000e+02   6.84498525e-02] 100
55.0 55.0 [   1.  250.   50.] [  1.00000000e+00   2.50000000e+02   2.51921938e-02] 100
55.0 55.0 [   1.  250.   50.] [  1.00000000e+00   2.50000000e+02   9.26916624e-03] 100
55.0 55.0 [   1.  250.   50.] [  1.00000000e+00   2.50000000e+02   3.41013551e-03] 100

only mod_H seems to be changing and it is rapidly going to zero.