Parameter unable to change when using Append Queries (multiple db sources)

Hi everyone

I've design and publish a report that get data through SQL with PowerBI parameters from different db and using PowerBI Append queries combine into one table.
I got error When I try to change parameters on PowerBI Online.

Does anybody know is this an limitation on PowerBI or Have another way to solve this problem?

I need to design a report with two requirements on PowerBI.
1. Combine serval database tables (with different db connection) into one table.
2. Parameterized queries when refresh data on PowerBI Online.

I will explain my design in detail below.

I created 2 parameters, all text and required.

I connect 2 sources, one from MySQL, another from SQL Server and both have parameter in SQL.

1. MySQL

2. SQLServer

I combine 2 queries by using Append Queries as new.

The data is now combine perfectly into one Table.

After publish to PowerBI Online.
I've also setup on-permises gateway.

And data refresh is no problem.

Finally I want to change parameter and refresh on PowerBI Online.

Change parameter values

it shows error when click update button.