After updating from an older to the current version (3.0.0) I noticed that old Math functions do not work anymore (e.g. padding: 30px / 2 will be create output padding: 30px / 2 instead of padding: 15px). To get it back to run, I looked into the current documentation of less v4 and needed to replace the configuration-option strictMath:false with math: 'always'. this worked for the old code (calculations without parens).

This is due to an update to less 4, which I found in your changelog.

strictMath is depracted (and does not work correctly anymore)

math has the following options:

• always (3.x default) - Less eagerly does math
• parens-division (4.0 default) - No division is performed outside of parens using / operator (but can be "forced" outside of parens with ./ operator - ./ is deprecated)
• parens | strict - Parens required for all math expressions.
• strict-legacy (removed in 4.0) - In some cases, math will not be evaluated if any part of the expression cannot be evaluated.

Further information can be found here: https://lesscss.org/usage/#less-options-math