43 GHz total intensity (Stokes I) VLBA images of S4 0954+65. Panels (A), (B), (C), and (D) show the parsec-scale maps of the compact core of the source from data obtained on 2023 April 2 (MJD 60036; about two months before the IXPE observation), 2023 May 21 (MJD 60085; five days before the IXPE pointing), 2023 June 1 (MJD 60096; during the IXPE pointing and in the vicinity of the peak of the optical-X-ray flare), and 2023 July 1 (MJD 60126; around one month after the IXPE pointing), respectively. The bottom-left white circle is has a radius of 0.2 mas and is the FWHM of the common convolving beam. The circular contours are Stokes I, between 10⁻⁶ and 10⁻³ Jy in log steps. The general direction of the jet is consistently northwest (−42° ±6°). In panel (A), a component (Q1) north-northwest of the compact core (C) appears to separate from the core after being “ejected”. The polarization angles of both C and Q1 are ∼115°. In panel (B), the polarization angles of both C and Q1 appear to have rotated to ∼35°. In panel (C), the polarization angle of C remains comparable to its value in (B), but that of Q1 has rotated by ∼100° compared to its value in (B). In panel (D), the polarization angle of C is 132°, while that of Q1 is 86°. In each panel, the angular size and polarization angle of the two components are represented by the circular symbols on the left (orange is used for the core component C and cyan is used for the moving component Q1): the radius of the circle symbolizes the angular size of each component (proportional to the FWHM of the intensity), while the orientation of the line through the circle visualizes the direction of the polarization angle.