I can confirm this, but I don't understand it. If you instead do

import matplotlib.pyplot as plt

# plt.rcParams['figure.autolayout'] = 'True'
 
plt.figure(layout='tight')
plt.plot([1, 2, 3], [1, 2, 3], 'o-')
plt.title(r'$\sum_{i=0}^{\infty} x_i$ just a test')
plt.savefig('test2.eps', format='eps')

it works fine.

If you use the rcParam and save as PDF it works fine. So I'm not sure why the ps backend is doing something different.

Same behaviour with plt.rcParams['figure.constrained_layout.use'] = True.

Still not fixed in 3.5.1

someone will have to dig into it before it gets fixed.

plt.figure(layout='tight')

I'm not sure how you got this to work, I see no appreciable difference in the file between the rcParam vs the parameter (i.e., both are broken).

Oh good, I must have been mixing up files somehow. Glad that it is consistent between the ways to set tight_layout...

I've just tested it out and...

plt.figure(layout='tight')

gives a broken result like with the rcParam.

But

plt.tight_layout()

does not. 🤔

I've just tested it out and...

plt.figure(layout='tight')

gives a broken result like with the rcParam.

But

plt.tight_layout()

does not. thinking

Same here with version 3.5.1 in archlinux.
And some lines are lost at the end of broken eps, like gsave, grestore things:

 FontName currentdict end definefont pop
 end
 %%EndProlog
 mpldict begin
 68.4 288 translate
 475.2 216 0 0 clipbox
-gsave
-0 0 m
-475.2 0 l
-475.2 216 l
-0 216 l
-cl
-1.000 setgray
-fill
-grestore
-
-................ more lines
-
-gsave
-
-384.960000 50.672828 translate
-0.000000 rotate
-0.000000 0 m /T glyphshow
-grestore

 end
 showpage