A) farmers use it as a crop dissicant in large quantities to make their crops cheaper to harvest, outside the spec of the product and
B) when it's used in unsuitable soil, temperature, and humidity conditions.
In the right conditions it has a half life of a few days and will be completely inert in a couple of weeks. This is a relatively small impact for a pretty big benefit. In poorly suited conditions it can persist for months or years.
We should just make it legal for use in situations where it decays quickly and harmlessly and disallow it's use in jurisdictions where the conditions are not appropriate for it's use. It's just a chemical, like any other chemical as long as it's used responsibly it can deliver incredible benefits. In this case cost-effectively feeding the world.
If the price for all that is some impairment to bumblebees for a few weeks maybe we should weigh that against the benefits and make a rational decision.