According to the Law Commission report cited these forays into PR are not new:
“Various progressive and united farmers’ parties also helped encourage electoral reform in the wake of World War I, culminating in the adoption of proportional representation for municipal elections in all four western provinces. Manitoba and Alberta also adopted alternative voting systems (notably the single transferable vote for provincial elections in urban ridings) and the alternative vote in rural ridings.
“These systems were in place from the early 1920s until the mid-1950s, when they were replaced by first-past-the-post systems.
“In many instances, proportional representation systems were replaced in order to quell opposition parties that had begun to challenge ruling governments.” — Voting Counts: Electoral Reform for Canada, p 26–27