The LMH1983 loop band width is the function of frequency gain of the VCXO used with.
Referring the datasheet, the bandwidth circulation refers the absolute pull in range.
It is the minimum frequency gain. Actual VCXO may have much larger gain.
How much validation did you count on when you design the loop band width of the
Evaluation board.
If the gain validate up to 200% or 300%, does the board works without any problem?
I wonder if you can provide Spice model of the phase detector (woth dividor paramter) and VCXO (with gain parameters)
If so, you can simulate the transient response and response on frequency domain using TINA TI