Is it unusual for an entity to report significant increase in cash from operating activities but a decrease in the total amount of cash?

Not very unusual. Total Cash Flow is the total from cash from opertating activities, investing activities and financing activites.

Postive Operating CF and negative Total CF could mean heavy investement for future growth (Plant, Property, Equipment etc) or the repayment of debt (or Capital Restructuring- share repurchase etc)

I would say that the inverse, while still not unusual would be somewhat concerning. Where Operating CF is negative and Total CF is positive. As this would mean your operations are not generating cash and you have resorted to Sale of Assets, Acquiring Loans, Share Sales etc to generate Cash.

The "unsualness" is all dependant on company policy.