Few valid cron expression can not convert to human format

[carlosnunesjr]

Cron Expression (cron to use bimontly) 0 14 16 25 /2 ?

Cron Expression (cron to use quarterly) 0 14 16 25 /3 ?

Cron Expression (cron to use semianual) 0 14 16 25 /6 ?

Expected Output At 12:23 PM, every two months - (cron to use bimontly) At 12:23 PM, every three months - (cron to use quarterly) At 12:23 PM, every three months - (cron to use semianual)

Actual Output Unknown Error: Error: month part must be >= 1 and <= 12

Prerequisites

• [x ] The cron expression being passed in is a valid expression. cRonstrue does not validate expressions and assumes the one you pass is already valid. See the FAQ for more details.

[bradymholt]

I don't think those expressions are valid, at least with most cron implementations. The interval needs to be proceeded by * like 0 14 16 25 */2 ?.