Here is a summary of the discussion on this issue here, and a response from Delta.
1. Ecoflow delta1300 has a floating ground
-issue is this safe?
2. Ecoflow has a mechanical issue being reversed polarity. You cannot plug in a three-pronged plug. The issue is that the large slot is on the right, whereas a US outlet the larger slot is on left. Any 2 blade cord works ok, and there is a hole for the grounding plug, not grounded.
3. Delta Response: We are cooperating with UL standards, Delta is using off-grid inverters which do not require between the neutral and hotwires. IF YOU NEED TO USE A SPECIFIC APPLIANCE THAT FEATURES A THREE-PRONGED POLARIZED PLUG, WE CAN PROVIDE A POLARIZED GROUNDING ADAPTER TO ACCOMMODATE YOUR NEEDS.
Will is this a problem? Seems like it is as they admit that an adapter is needed to make it safe.