Nexus pypi repository fails to update index

Nexus version PRO 3.70.1-02
Users of our internal repository cannot pip install latest uploaded packages. You can see them in the web interface, and you can install them using the direct URL, but pip install results in:

(test) mac-011:glo12_cylc gturek$ pip install lib-pyt==3.0.15
Looking in indexes: https://nexus.mercator-ocean.fr/repository/pypi-all/simple/, https://nexus.mercator-ocean.fr/repository/pypi-internal/simple/
ERROR: Ignored the following versions that require a different python version: 2.0.3 Requires-Python >=3.6,<3.7; 2.0.4 Requires-Python >=3.6,<3.7; 2.0.5 Requires-Python >=3.6,<3.7; 2.0.6 Requires-Python >=3.6,<3.7
ERROR: Could not find a version that satisfies the requirement lib-pyt==3.0.15 (from versions: 2.0.2, 2.0.7, 2.0.8, 2.0.9, 2.0.10, 2.0.11, 2.0.12, 2.0.13, 2.0.14, 2.0.15, 2.0.16, 2.0.17, 2.0.18, 2.0.19, 2.0.20, 2.0.21, 2.0.22, 2.0.23, 2.0.24, 2.0.25, 2.0.26, 2.0.27, 2.0.28, 2.0.29, 2.0.30, 2.0.31, 2.0.32, 2.0.33, 2.0.34, 2.0.35, 2.0.36, 2.0.37, 2.0.38, 2.0.39, 2.0.40, 2.0.41, 2.0.42, 2.0.43, 2.0.44, 2.0.45, 3.0.2, 3.0.3, 3.0.4)
ERROR: No matching distribution found for lib-pyt==3.0.15

I tried to rebuild the index but it has not fixed this problem.
Any ideas?
Thanx

This actually appears to be a problem with this one component only
Reuploading it seems to solve the problem, but it about 10 versions are undiscoverable.
What could cause this issue?