Realm doesn't replace world when replacing world.

I am now noticing Mojang isn't replying so I will place this elsewhere.

You know that there is a lot of bugs reported and only a few people working on developing realms? Especially with relatively minor bugs this obviously doesn't take topmost priority.
Also, in this case it might be better to contact support https://help.mojang.com/

I've been having this trouble since at least 1.0.6, how ever i skipped a few updates so it has possibly existed since 1.0.5-4?

I can reset and replace realms with no problem as long as the realm is a vanilla map. Currently, no world with add-ons can be uploaded as a new realm or used to replace a current realm.

I have tried this with multiple android and windows devices AND multiple Realm accounts using various maps with and without addons.

I am having the same issue. I was able to Replace World successfully when I first bought my realm about 5 months ago, but since the latest update (when the coordinates were added without cheating) I have not been able to replace my world. At first I thought it was glitching due to the fact that I had downloaded the world and activated map coordinates and then tried to Replace World with the coordinates on, but when I tried to Replace World with multiple other vanilla/default settings worlds none of them worked either. On both PC (Windows 10) and XboxOne, the "Uploading World" dialogue pops up and the progress meter stays at 0%. A few seconds later a dialogue box pops up saying "Transfer Complete" (Or something like that) but nothing happens. The progress meter still says 0% of ###MB, and the only option is to click "Cancel" or reset/force quit.

I appear to still be having this issue even now February 2019

I am still having this issue. What gives? I should be able to upload my realm...

issue is still happening in Jan 2020