Dax formula

Glad to hear it worked. Try this updated DAX...

measure 2 =
VAR _mat = MAX('Operation description'[Merged1])
VAR _firstRed =
MINX(
FILTER(
ALL('Operation description'),
'Operation description'[STATUS] = "RED" &&
'Operation description'[Merged1] = _mat
),
'Operation description'[Column 3]
)
VAR _lastGreen =
MAXX(
FILTER(
ALL('Operation description'),
'Operation description'[STATUS] = "GREEN" &&
'Operation description'[Merged1] = _mat
),
'Operation description'[Column 3]
)
VAR _greenExists =
CALCULATE(
COUNTROWS(
FILTER(
ALL('Operation description'),
'Operation description'[STATUS] = "GREEN"
)
)
)
VAR _laststep = IF(_greenExists > 0, _lastGreen, _firstRed)
VAR _result =
CALCULATE(
COUNTROWS(
FILTER(
ALL('Operation description'),
'Operation description'[Column 3] = _laststep &&
'Operation description'[Merged1] = _mat
)
)
)
RETURN
IF(
MAX('Operation description'[Column 3]) = _laststep,
_result,
BLANK()
)

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