ADDITIONAL SYSTEM INFORMATION :
OS : Windows 10
JRE : 11.8 and 11.9

A DESCRIPTION OF THE PROBLEM :
Using the following code on JDK 11.8/11.9 -
LocalDate dt = LocalDate.now();
String dtStr= dt.format(DateTimeFormatter.ofPattern("dd-MMM-yyyy"));

Output is -

dt= 2020-11-20
dtStr = 20-Nov.-2020

Notice the "." in dtStr which is incorrect.
LocalDateTime with the same format pattern("dd-MMM-yyyy") also yields the "." in the resultant string.

The same error is not observed on JDK 8. I have not tested with JDK>11.

REGRESSION : Last worked in version 8

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the following code snippet -
LocalDate dt = LocalDate.now();
String dtStr= dt.format(DateTimeFormatter.ofPattern("dd-MMM-yyyy"));

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
dt= 2020-11-20
dtStr = 20-Nov-2020
ACTUAL -
dt= 2020-11-20
dtStr = 20-Nov.-2020

CUSTOMER SUBMITTED WORKAROUND :
Using substring at the moment to overcome the "." in the resultant string.

FREQUENCY : always