An idea flashed on me that the interpreter name / b i n / b a s h (without spaces) is the phrase letting the fora software deny the post. So I try the idea. Here goes the amended version.
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Hello
IMHO, Format > Font > Capitalization is one of the most confusing features of Numbers and Pages. It never change the text data itself but only the text "appearance" just as changing font does nevertheless the text case is not the matter of glyphs but the code points. This is the reason why you see the said behaviour.
E.g., enter loweccase text, apply Format > Font > Capitalization > Title, copy the text, paste into TextEdit and you'll see the lowecase text.
In order to preserve the capitalization between applications, that includes exporting to CSV, text must consists of exact code points of coded character set which by design implements character case by distinct code point.
There're several ways to realise that and here I'd like to present a method using services. If you have already installed any text services that can change text case, just use it. Otherwise it is simple to create your own services using Automator.app. Recipe is as follows.
1) Launch Automator.app, select Service template, add Run Shell Script action (from left pane to right workflow editor pane).
2) Set service's properties such that
Service receives selected [text] in [any application]
Replaces selected text [checked]
3) Set Run Shell Script action's properties such that
Shell = / b i n / b a s h (actually without spaces inbetween)
Pass input = as arguments
Code =
perl -CSDA -pe 's/\b\w+/\u\L$&/g' <<< "$@"
Now service workflow looks like this:

4) Save the service workflow with descriptive name such as "change case to Title Case".
In order to use the service, first select text in any application and select the service from [Application] > Services menu.
In Numbers.app, for example, you may copy the column, paste it into a new text box, select the text in the text box, call the service and the text will be replaced with Title Cased text. Then copy the converted text and paste to the original column. Done.
Of course, you may copy the column in Numbers to TextEdit, apply the service in TextEdit and copy it back to the column in Numbers.
If you wish you may assign keyboard shortcut for the service by using System Prefenencs.
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You may also create services for lowercase and UPPERCASE by changing the code for Run Shell Script action as follows.
For lowercase (change case to lowercase):
perl -CSDA -pe 's/\b\w+/\L$&/g' <<< "$@"
For UPPERCASE (change case to UPPERCASE):
perl -CSDA -pe 's/\b\w+/\U$&/g' <<< "$@"
Hope this may help,
H
PS. Bingo. / b i n / b a s h (without spaces) is being filtered. But why ???.
Message was edited by: Hiroto (added PS)