Inconsistent sentence splitting when sentence boundary is defined by `r'[}\]]\.\s[A-Z]'`

[chguenther]

Here is an example text that fails:
'''Ms. X was admitted on date]. Ultrasound
at the time of admission demonstrated pancreatic duct dilatation and
edematous gallbladder. She was admitted to the ICU.'''
This text should be split into three sentences. However, it is only split into two sentences. There is no sentence split between the first two sentences, i.e., between "]." and "Ultrasound".
The same behavior was observed when the "]" was replaced by a "}". It works properly when the "]" is replaced by a ")". No other characters were tried.

Here are some observations that might help to pinpoint the issue.

1. It works properly with this text
   '''Ms. X was admitted on date]. Ultrasound
   at the time of admission demonstrated pancreatic duct dilatation and
   edematous gallbladder.'''
   Note that this text does not contain the third sentence.
2. It works properly when a "The" is inserted at the beginning of the second sentence before "Ultrasound" to obtain this text:
   '''Ms. X was admitted on date]. The Ultrasound
   at the time of admission demonstrated pancreatic duct dilatation and
   edematous gallbladder. She was admitted to the ICU.'''