Freeform cannot sync images from Macbook to iPad

Hello! I am a user of MacBook Pro and iPad Pro. Recently, I am trying the new Freeform App in both of my devices and I love it very much! But I am currently facing problem with the sync of Freeform document. When I insert images from my Mac to the Freeform Document, it cannot sync to my iPad and showing a placeholder named "Adding image..." But all other changes can sync to my iPad. Besides, the image add from my iPad can successfully transfer to Mac. I am wondering if anyone have the same issue? Is there any solution to this issue?

I have tried the following methods, but none of them works for me:

• Wait. I have wait for several days but in vein.
• Restart my Mac and iPad.
• Restart the Freeform in both device.

The phenomenon looks like following in iPad:

Thanks!

Sheng