First 40 characters of long text in IA07 is not getting displayed

I am working on a development to save long text for operations in IA07 transaction  as shown in attached screen-shot:

For this, I have used SAVE_TEXT FM. When SAVE_TEXT FM is executed, all the lines are saved as long text.

But,initial 40 characters of line 1 are not visible.

For e.g, if 10 lines are passed to SAVE_TEXT, then initial 40 characters of line 1 are not visible, other lines are visible as shown in below screen-shot:

The initial 40 characters of line 1 in Long Text is also displayed in Operation description field which is not getting

displayed for my case as shown in below screen-shot:

However, when I execute READ_TEXT FM, it fetches the entire long text in internal table including initial 40 characters of 1st line as shown in attached screen-shot.

Please help on this.