RE:Down 5%Strathcona trading at $28.50 is equivalent to PIPE trading at $1.94 which is where PIPE last traded before the exchange of shares.
Last time I checked, it was mostly Goldman Sachs that was slowly selling shares into the market.
https://money.tmx.com/en/quote/SCR/trade-history They are likely slowly liquidating a position so the market does not get too spooked and drop like a rock with fewer buyers than sellers. SCR is not going anywhere until this overhang is sold off. It is impossible to know if this will go on for a day or two or maybe for weeks or months.
I am not overly surprised that this is happening. Some wanted out the moment this deal was finalized and some decided to wait until SCR started trading before unloading shares. The bleeding will stop someday as long as GMT does not slowly start selling all of their shares.