triplet bracket disappear

[Nick Didkovsky]

Hello,

I am using the following commands to get a short 6-measure, 9-staff 
piece to fit on one page:
#(set-default-paper-size "letter" 'landscape)
#(set-global-staff-size 13)

At this size, I discovered some (not all) of by triplet brackets disappear.

Has anyone experienced this? Is there a fix (other than using a larger 
global staff size)?

Thank-you
Nick Didkovsky