PA_BUDGET_PUB.UPDATE_BUDGET: budget lines are not updated

hi!

I was asked to investigate an issue when existing budget lines are not updated, for instance a revenue is not updated.

I've checked the code in PA_BUDGET_PUB.UPDATE_BUDGET procedure and it looks like budget lines are updated based on resource assignment ID, currency code and budget line start date:

UPDATE PA_BUDGET_LINES

SET  REVENUE = :xRevenue,

LAST_UPDATE_DATE = :xLastUpdateDate,

LAST_UPDATED_BY = 28032,

LAST_UPDATE_LOGIN = -1

WHERE RESOURCE_ASSIGNMENT_ID  = 4814795

AND START_DATE = :xStartDate

AND TXN_CURRENCY_CODE = 'NOK'

but Start Date was not changed, only the revenue value was changed. I started to dig more in the code and found some strange piece of code and now I'm confused what is purpose of this code. Here it is the listing: