Use simple assignment whenever possible:
<nowiki>
| label6 = Start Date
| data6 = [[Start date::{{{Start date|}}}]]
</nowiki>
If you have to use an array ref, here's the syntax:
<nowiki>
| label5 = Owner
| data5 = {{#arraymap:{{{Owner|}}}|,|x|[[Owner::x]]}}
</nowiki>