Patrice, Are you by chance using the European "," as the decimal delimiter? Since you are mentioning metric sizing and your address seems to be in France, I thought it might be a possibility. There is definitely a number of problems in DXP caused by the use of a "," as a decimal point. In short, don't do that, set your machine O/S to use the "." convention for decimals. They are supposedly working on a fix for that, maybe in SP5.
Other than that, why ask your questions here, the Altium DXP forum will probably get you more help and a lot faster? Even the Altium tech support and some of the actual developers are online there, besides a large number of users. And if there is no answer or work-around, then you have also informed the developers without any additional effort.
Actually, should I have even asked such a stupid question? Your software is probably pirated, that is why you don't ask there.
Another possibility, switch to imperial, see if that may work. That may not work any better if you designed your pads in metric, then they are just as likely to have decimals in their imperial sizing after conversion.