No crash report is generated, although this part from the log seems to describe the cause (feature order cycle)
Caused by: java.lang.IllegalStateException: A feature cycle was found.
Cycle:
At step 9
Feature 'minecraft:brown_mushroom_taiga'
must be before 'minecraft:red_mushroom_taiga' (defined in 'minecraft:taiga' at index 4, 5 and 2 others)
must be before 'nomansland:patch_field_mushroom_normal' (defined in 'minecraft:taiga' at index 5, 12 and 1 others)
must be before 'nomansland:patch_roots' (defined in 'minecraft:birch_forest' at index 13, 16 and 26 others)
must be before 'nomansland:patch_cattail' (defined in 'minecraft:birch_forest' at index 16, 17 and 42 others)
must be before 'nomansland:patch_reeds' (defined in 'minecraft:birch_forest' at index 17, 18 and 42 others)
must be before 'nomansland:patch_waterlily_common' (defined in 'minecraft:birch_forest' at index 18, 19 and 42 others)
must be before 'minecraft:patch_dead_bush' (defined in 'minecraft:mushroom_fields' at index 8, 9)
must be before 'nomansland:patch_dried_grass_mycelium' (defined in 'minecraft:mushroom_fields' at index 9, 10)
must be before 'nomansland:patch_duckweed_sparse' (defined in 'minecraft:mushroom_fields' at index 10, 11)
must be before 'nomansland:patch_hearty_succulent' (defined in 'minecraft:jungle' at index 20, 21)
must be before 'minecraft:patch_large_fern' (defined in 'minecraft:jungle' at index 21, 22)
must be before 'minecraft:brown_mushroom_taiga' (defined in 'minecraft:taiga' at index 1, 4 and 1 others)
I've tried removing blueprint, although the issue still persists. Reverting to NML 1.2.3 fixes it