RESMPx bug

[thrust26]

When doing the following each frame:

    lda     #2
    sta     RESMP0
    sta     RESMP1
    lda     #0
    sta     RESMP0
    sta     RESMP1
    sta     WSYNC
    SLEEP   45
    sta     RESP0
    sta     RESP1
    sta     RESBL

Then Stella positions the missiles at the center of their players (right of the middle of the screen). While on my console they remain at the very left.