Circular interpolation Fagor 8050, 8060 ...

Hello

First of all, since this is my first post, I would like to thank all of you who make this forum possible.

Although I have programming knowledge in other areas, I have recently started to learn CNC programming and I have been reading this forum which contains a lot of interesting information.

Today I would like to create a new post to try to solve a doubt about the circular interpolation in the Fagor 8050, 8060, 8070 controllers... that probably is simple but I have not been able to solve (The tests have been done on the Fagor 8070 lathe simulator):

To perform a circular interpolation there are two ways in which it can be done, indicating the end point and radius or with incremental coordinates using i, j, k.
In the first way it works perfectly, for example:

G00 X40 Z60
G18 G03 X90 X90 Z110 R50;

However using incremental coordinates:

G00 X40 Z60
G18 G03 X90 Z110 I50 K0

I get error : 1028 'The difference between the programmed center and the calculated one is too large'.

But according to the documentation I think the command would be correct. Has anyone had a similar problem?

Thanks to everyone for your comments