You're asking why this specifically has gone up? Probably two things - the markets have recovered a little lately, and the large investors were probably getting worried about the huge dividend. When a company cuts, sometimes the price goes down ("oh noes! they're borken!!"), but often the price goes up ("ok, management aren't stupid - they are being sensible/conserving cash/paying down debt").
Going forward, if you're not wedded to D, but do want to keep some REIT stuff going on, you may want to sell (yay, cap loss), and buy something like VRE (Vanguard REIT ETF Canada). If you want to keep D, go for it.
LOTS of stuff is down since last year.