Flat Rate Shipping * [qty]not updating

Since updating to version 8.4.0, the flat rate shipping class cost does not save the qty portion. For example, I enter $12.95 * [qty] and as soon as I hit save the * [qty] drops off and only $12.95 is saved. I tried disabling plugins and changed themes and nothing works. Am I able to downgrade to a previous version? The old version works, but this one doesn’t.