P: Smart Collection bug with Title doesn't contain rule and letter 't'

Hi,

There are various articles on smart collections that check if the "Title" field is filled or not. Because the "Title" field doesn't have an "is empty" like function, the sugested solution is to use:

Title doesn't contain a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z

But there is a bug in this rule. I found that the letter 't' is causing a problem. The letter 't' seems to include all characters.

Situation:
Four images that have a their Title field as follows:
Image 1:
Image 2: 2014-01 - Street Photography.dng
Image 3: 2014-01
Image 4: Some Image

(Image 1 has an empty title)

Four smart collections with the following rules:
Collection 1: Title doesn't contain a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z
Collection 2: Title doesn't contain 0,1,2,3,4,5,6,7,8,9
Collection 3: Title doesn't contain a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,u,v,w,x,y,z
Collection 4: Title doesn't contain t

My expected result of the smart collection is:
Collection 1: Image 1 and Image 3
Collection 2: Image 1 and Image 4
Collection 3: Image 1 and Image 3
Collection 4: Image 1, Image 3 and Image 4

The actual result of the smart collection is:
Collection 1: Image 1
Collection 2: Image 1 and Image 4
Collection 3: Image 1 and Image 3
Collection 4: Image 1

I'm using Lightroom 5.7 on a MacBook Pro 17" (mid 2010), i7 @ 2.66GHz, 8GB RAM and 2 x 240GB SSD's running on OS X 10.10.1

My questions are:
Can anyone, specially from the Adobe Lightroom team, confirm this?
How to solve this issue?