SU Tau started fading?

Sato-san has pointed out the gradual fading.

YYYYMMDD(UT) mag observer 20230318.8813 100 (Eddy Muyllaert) 20230319.439 105 (Takuichiro Onishi) 20230319.4497 10.13V (Minoru Sato) 20230319.549 101 (Yoshiyasu Sato) 20230319.8153 99 (Jose Ripero) 20230320.4490 10.18V (Minoru Sato) 20230321.8132 101 (Eddy Muyllaert) 20230325.4272 10.35V (Minoru Sato) 20230326.5031 103cG (Yutaka Maeda) 20230326.5736 104V (Masayuki Moriyama) 20230327.4096 10.52V (Minoru Sato) 20230327.8340 100 (Eddy Muyllaert) 20230328.4183 10.55V (Minoru Sato) 20230328.5680 105V (Masayuki Moriyama) 20230329.4157 10.59V (Minoru Sato) 20230329.8438 100 (Eddy Muyllaert) 20230330.4337 10.66V (Minoru Sato) 20230330.451 104 (Tsuneo Horie) 20230331.437 104 (Tsuneo Horie) 20230331.465 107 (Hiroyuki Maehara) 20230331.5062 106cG (Yutaka Maeda) 20230331.5983 107V (Masayuki Moriyama) 20230401.542 111 (Takuichiro Onishi)