Mermaid in tabs - docusaurus

Question

The arrows are not displayed in the second tab. Bug?
It works here https://docusaurus.io/tests/pages/diagrams#mermaid-in-tabs
I have:
a) In "tab-a", the arrows are displayed:
b) But in "tab-b", the arrows are not displayed:
Version of docusaurus: 2.2.0
Type files: .md or .mdx
import Tabs from '#theme/Tabs';
import TabItem from '#theme/TabItem';
<Tabs>
<TabItem value="tab-a">
The following mermaid diagram is shown:
```mermaid
graph LR
a ---> c(10)
b ---> c(10)
```
</TabItem>
<TabItem value="tab-b">
This mermaid diagram is not displayed:
```mermaid
graph LR
d ---> z(42)
e ---> z(42)
```
</TabItem>
</Tabs>

Answer 1

I copy/pasted the code from your docussaurus reference, so I can see the problem.
I believe that is a bug indeed...
This is how I managed to work-around:
import Tabs from '#theme/Tabs';
import TabItem from '#theme/TabItem';
# Mermaid in tabs
<!-- [start] add this to avoid the possible bug. Note: the empty line before [```] is necessary -->
```mermaid
flowchart TD
```
<!-- [end] add this to avoid the possible bug -->
<Tabs>
<TabItem value="tab-a">
```mermaid
graph LR
a ---> c(10)
b ---> c(10)
```
</TabItem>
<TabItem value="tab-b">
```mermaid
graph LR
d ---> z(42)
e ---> z(42)
```
</TabItem>
</Tabs>
NOTES
I downloaded the page that worked, from docusaurus;
I trimmed all code, until it broke;
I tested until I found a way to render the "wanted" result, without any extra "artifacts";
Now we have a working code, but it is a workaround one.