Problem with SENDMAIL function in IDE BASIC Script

I have a problem with the SENDMAIL function in the IDE BASIC script,
The mails are being sent to the corresponding addresses, but if I send the same message to several recipients, with for example : "Adr_mail$=MEM_Adr_Mail_1@ + “;” + MEM_Adr_Mail_2@ + “;” + MEM_Adr_Mail_3@ + “;” + MEM_Adr_Mail_4@ + “;” " => Regarding the date, the time and the numeric values that I send in the mail => there are small differences in values.
This phenomenon doesn’t occur when I use an unique mail address, Can you help me solve this problem ?