Weird problem with the campaign.

[Skarmy]

I'm up to Happy Days, and I have 2 missions that cover the same zone of operation, one where I must sink 10 allied ships, and another that requires 200,000 tonnes of merchant shipping destroyed- I took the mission for 10 ships- I sunk a British carrier and Battleship (I think these 2 counted any ways), and one other misc merchant and they counted towards my number (merch counted towards the other mission objective of 200,000 tons) And then I went home and ended patrol because I sustained damage during a deep escape dive.

I requested the mission again and went to my zone sunk some merch's BDu told me to patrol wherever and the RTB- I noticed though that the ships I'm sinking isn't counting towards my number of ships sunk, BUT the tonnage is counting towards the other objective- What's going on?

Could it be because the mission says to sink 10 ships transporting war supplies and what I'm sinking isn't actually carrying war supplies?