Using R1C1 reference style, converting from a relative to an absolute reference (using Shift+F4), Calc incorrectly converts the reference.

--==  To reproduce ==--

Open Calc
Tools > Options > LibreOffice Calc > Formula > Formula options > Formula syntax > Excel R1C1 > OK

In row 1, column 1 (usually A1) enter the data: 1
In row 1, column 2 (usually B2) enter the data: 2
In row 2, column 1 (usually A2) enter the data: 3
In row 2, column 2 (usually B2) enter (without quotes) the formula: "= R1C1"

Press "Enter" to confirm input
 - the formula returns "1", as it should -

Select the reference "R1C1" in the formula bar (still in cell B2)
Press "Shift+F4"
 - the reference changes to "R1C" (incorrect, it should be R1C[-1]) -
Press "Enter" to confirm input
 - the formula returns "2", this is incorrect (should still return "1") -

Select the reference "R1C" in the formula bar (still in cell B2)
Press "Shift+F4" again
 - the reference changes to "RC1" (incorrect, it should be R[-1]C1) -
Press "Enter" to confirm input
 - the formula returns "3", this is incorrect (should still return "1") -

Select the reference "RC1" in the formula bar (still in cell B2)
Press "Shift+F4" again
 - the reference changes to "RC" (incorrect, it should be R[-1]C[-1]) -
Press "Enter" to confirm input
 - the formula returns "Err:522", this is incorrect (should still return "1") -

 --== End of reproduction ==-- 

Using LibreOfficePortable 3.3.2 as downloaded from http://portableapps.com/apps/office/libreoffice_portable
Running off local drive (C:\PortableApps\LibreOfficePortable) in Win7 64bit
About:
LibreOffice 3.3.2
OOO330m19 (Build:202)
tag libreoffice-3.3.2.2 

Apologies for the wordy post, but I wanted to avoid misinterpretation as far as possible.