Getting error "recurFrequencyUnit must be day|weekpwd|month|year"

[sunnycs121]

CMS: Drupal 7.69
CiviCRM version: 5.21.2
Payment Processor: Stripe (extension version: 6.3.2)
Webform CiviCRM Integration module version: 7.x-5.0

Issue description:

When webform is submitted, selecting it to be a one time payment (not recurring), it appears submission process still thinks it a recurring payment and gives following error:

recurFrequencyUnit must be day|weekpwd|month|year

I checked civicrm config log and found following message (no error/backtrace):

Apr 01 09:36:18 [warning] Deprecated code: We have translated 'frequency_unit' to 'recurFrequencyUnit' for you, but please update your code to use the propper setters and getters.