Mermaid subgraph has no directional arrows

Things I have tried

flowchart TB
	c1-->a2
	subgraph one
		a1-->a2
	end
	subgraph two
		b1-->b2
	end
	subgraph three
		c1-->c2
	end
	one --> two
	three --> two 
	two --> c2

What I expected:

flowcharts using subgraph and linked with arrows
Snipaste_2022-09-12_14-28-07

What I actually got:

No Arrows!!! Even I used -->
Snipaste_2022-09-12_14-24-21

What I’m trying to do

So, how to fix it?
Thanks

Worked for me.

Using Minimal Theme.

can confirm I get the expected arrows in v0.15.9 with 80s Neon theme