That's not a bug, if you wanted to get rid of the other offer, you should have offered a far bigger transfer fee. The X value that determines if the other offer competes with yours was less than 1% higher, the system rarely would remove the other offer. The system considered both offers, when both offers competed, it choosed the highest wage, since it was no highest wage, it decided randomly.
In situations like that (only one offer), offer an extra G in wage, not fee. I can tell you for sure, if you would've offered 3.534 as weekly wage, the player would be yours by now.