Logic syntax on Wolfram|Alpha

Questions
,
1

Hi, can anyone explain why "truth table ((a and (b and c)) equivalent ((a and b) and c)) " doesn’t work on Wolfram|Alpha?

2

This

(a && (b && c))==((a && b) && c)

returns

True (for any a,b,c)
3

Thanks for your help. This is quite weird.
“truth table (a implies b) equivalent (not b implies not a)” works
but "truth table ((a and (b and c)) equivalent ((a and b) and c)) " doesn’t work,

4

We are currently fixing this issue