Cumulative - empty for months with no data

JoaoPvP , If you are using Year = max( year) Than is as good YTD ??

Voyages_agg_test = CALCULATE( COUNT(CE[Voyage]); FILTER( ALL('Calendar'); AND( 'Calendar'[Date] <= MAX(CE[COD]) ; YEAR('Calendar'[Date]) = YEAR( MAX('Calendar'[Date]) )) ))

Try like

Voyages_agg_test = CALCULATE( COUNT(CE[Voyage]); FILTER( ALL('Calendar'); AND( 'Calendar'[Date] <= MAX('Calendar'[Date] ) ; YEAR('Calendar'[Date]) = YEAR( MAX('Calendar'[Date]) )) )

because when COD is not there it will fail

you can have filter to stop at max cod value

like

Voyages_agg_test =
var _max = MAXX(allselected(CE),CE[COD])
return
CALCULATE( COUNT(CE[Voyage]); FILTER( ALL('Calendar'); 'Calendar'[Date] <= MAX('Calendar'[Date] ) && YEAR('Calendar'[Date]) = YEAR( MAX('Calendar'[Date]) &&
'Calendar'[Date] <= _max) ) )

For YTD refer : YTD Questions — Time Intelligence 1–5
https://medium.com/@amitchandak.1978/power-bi-ytd-questions-time-intelligence-1-5-e3174b39f38a