What version of HeroRotation are you using?

11.1.0.34

What version of HeroLib are you using?

11.1.0.11

What version of HeroDBC are you using?

11.1.0.06

What is the issue?

Fan of Knives is being suggested in pure single target with Vicious Venoms talented.

It may have only been a recent change to the APL with the tuning pass last week (?).

I think it's this line here (but I am no expert).

-- actions.direct+=/variable,name=fok_target_count,value=(buff.clear_the_witnesses.up -- &(spell_targets.fan_of_knives>=2-(buff.lingering_darkness.up|!talent.vicious_venoms))) -- |(spell_targets.fan_of_knives>=3-(talent.momentum_of_despair&talent.thrown_precision)+talent.vicious_venoms+talent.blindside)

The debug output for the line was 'Cast Fan of Knives'

Icon Behavior

None

From the line quoted, the target count can be 1 if the Clear the Witnesses buff and Lingering Darkness buff are both active.

it was added in this commit in SimC 2 weeks ago:
simulationcraft/simc@44a0689