Is NWCInv included in OCF? (Equity has different explaination from corporate finance)

In Corporate Finance, the OCF equals (S-C-D)(1-T)+D, which makes sense especially when there is no additional NWcInv in the operating period.
However, if the company has additional NWCInv every year in operating. Do we need to consider this NWCInv in the OCF calculating?
The NWCInv, in the beginning, is classified in outlay. And in the end, NWcInv is added back when calculating TNOCF (total non-operating cash flow). Looks like that in Corporate finance, the WcInv is not in an operating cash flow? Why buying inventory is not OCF?

But in Equity part, the CFO= Net income + NCC - WCInv. It contains WCInv.

Anyone has any idea?

Buying inventory is considered an operating cash flow activity.