Same expression working on one page but not on another

I have an array in a session variable

I am able to look up a value in it on one page using

 <button id="btn1" class="btn" 
dmx-text="session.data.stats.where('gid','A100','==')[0].FIB">Button</button>

but on another page this same expression is not working

<button id="btn2" class="btn bg-warning"
 dmx-text="session.data.stats.where('gid','A100','==')[0].FIB ">Button</button>

I have added session on both pages.
If i modify the expression to

 <button id="btn2" class="btn bg-warning" 
dmx-text="session.data.stats.[0].FIB">Button</button>

then i am able to make it work on the second page too. Why is the ‘where’ expression not working on the second page?