It is common, for a resource loaded online live from the internet, that, on occasion, the data will not arrive. Like typing in a website address and the website will load but the images won’t because the images are stored on a Content Delivery Network (CDN) and that network or a node of that network is overloaded, or unresponsive, corrupted or under attack. It’s not a joke, it’s technology and your processor, graphics card, isp and this forum can do absolutely nothing about it.
I wish there was a better answer but there is none to give. A typical flight for 40 minutes in FS2020 will transfer about 1GB of data, it is to be expected that (given the laws of large numbers) there will be data missing. It is what it is old sock.